<PAGE>
                                                                    EXHIBIT 4.13

================================================================================


                                     FORM OF


                            VALERO ENERGY CORPORATION


                               GUARANTEE AGREEMENT


                               VEC TRUST [ ] [ ]




                           ---------------------------


                         Dated as of             ,
                                     -------- ---  ----


                           ---------------------------



================================================================================

<PAGE>



                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                               PAGE
                                                                                                               ----
<S>               <C>                                                                                          <C>
                                                     ARTICLE I
                                                    DEFINITIONS

SECTION 1.01      Definitions.....................................................................................1

                                                    ARTICLE II
                                                TRUST INDENTURE ACT

SECTION 2.01      Trust Indenture Act; Application................................................................5
SECTION 2.02      Lists of Holders of Preferred Securities........................................................5
SECTION 2.03      Reports by the Guarantee Trustee................................................................6
SECTION 2.04      Periodic Reports to the Guarantee Trustee.......................................................6
SECTION 2.05      Evidence of Compliance with Conditions Precedent................................................6
SECTION 2.06      Events of Default; Waiver.......................................................................6
SECTION 2.07      Disclosure of Information.......................................................................7
SECTION 2.08      Conflicting Interest............................................................................7

                                                    ARTICLE III
                                POWERS, DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEE

SECTION 3.01      Powers and Duties of the Guarantee Trustee......................................................7
SECTION 3.02      Certain Rights and Duties of the Guarantee Trustee..............................................8
SECTION 3.03      Not Responsible for Recitals or Issuance of Guarantee..........................................10
SECTION 3.04      The Guarantee Trustee May Own Preferred Securities.............................................11
SECTION 3.05      Moneys Received by the Guarantee Trustee to Be Held in Trust Without
                  Interest.......................................................................................11
SECTION 3.06      Compensation and Expenses of Guarantee Trustee.................................................11

                                                    ARTICLE IV
                                                 GUARANTEE TRUSTEE

SECTION 4.01      Qualifications.................................................................................12
SECTION 4.02      Appointment, Removal and Resignation of the Guarantee Trustee..................................12

                                                     ARTICLE V
                                                     GUARANTEE

SECTION 5.01      Guarantee......................................................................................13
SECTION 5.02      Waiver of Notice...............................................................................13
SECTION 5.03      Obligations Not Affected.......................................................................13
SECTION 5.04      Enforcement of Guarantee.......................................................................14
SECTION 5.05      Guarantee of Payment...........................................................................15
SECTION 5.06      Subrogation....................................................................................15
SECTION 5.07      Independent Obligations........................................................................15
</TABLE>


                                        i

<PAGE>



<TABLE>
<S>               <C>                                                                                          <C>
                                                    ARTICLE VI
                                     LIMITATION OF TRANSACTIONS; SUBORDINATION

SECTION 6.01      Limitation of Transactions.....................................................................16
[SECTION 6.02     Subordination..................................................................................17

                                                    ARTICLE VII
                                                    TERMINATION

SECTION 7.01      Termination....................................................................................17

                                                   ARTICLE VIII
                                     LIMITATION OF LIABILITY; INDEMNIFICATION

SECTION 8.01      Exculpation....................................................................................17
SECTION 8.02      Indemnification................................................................................18
SECTION 8.03      Survive Termination............................................................................18

                                                    ARTICLE IX
                                                   MISCELLANEOUS

SECTION 9.01      Successors and Assigns.........................................................................18
SECTION 9.02      Amendments.....................................................................................19
SECTION 9.03      Notices........................................................................................19
SECTION 9.04      Genders........................................................................................20
SECTION 9.05      Benefit........................................................................................20
SECTION 9.06      Governing Law..................................................................................20
SECTION 9.07      Counterparts...................................................................................20
SECTION 9.08      [Exercise of Overallotment Option..............................................................20
SECTION 9.09      Limited Liability..............................................................................20
</TABLE>


                                       ii

<PAGE>



                               GUARANTEE AGREEMENT

                  This GUARANTEE AGREEMENT, dated as of __________, ____, is
executed and delivered by VALERO ENERGY CORPORATION, a Delaware corporation (the
"Guarantor"), and The Bank of New York, a national banking association, as the
initial Guarantee Trustee (as defined herein) for the benefit of the Holders (as
defined herein) from time to time of the Preferred Securities (as defined
herein) of VEC Trust [ ] [ ], a Delaware statutory business trust (the
"Issuer").

                  WHEREAS, pursuant to an Amended and Restated Declaration of
Trust (the "Declaration"), dated as of ______________, ____ among the trustees
of the Issuer named therein, Valero Energy Corporation, as Sponsor, and the
Holders from time to time of preferred undivided beneficial interests in the
assets of the Issuer, the Issuer may issue up to $_____________ aggregate
liquidation amount of its _____% [Convertible] Trust Preferred Securities (the
"Preferred Securities") representing preferred undivided beneficial interests in
the assets of the Issuer and having the terms set forth in the Declaration [, of
which $_____________ liquidation amount of Preferred Securities is being issued
as of the date hereof. Up to the remaining $______________ liquidation amount of
Preferred Securities may be issued by the Issuer if and to the extent that the
over-allotment option granted by the Guarantor and the Issuer pursuant to the
Underwriting Agreement (as defined in the Declaration) is exercised by the
Underwriters named in the Underwriting Agreement]; and

                  WHEREAS, as incentive for the Holders to purchase Preferred
Securities, the Guarantor desires to irrevocably and unconditionally agree, to
the extent set forth herein, to pay to the Holders the Guarantee Payments (as
defined herein) and to make certain other payments on the terms and conditions
set forth herein;

                  NOW, THEREFORE, in consideration of the purchase by the
initial purchasers thereof of Preferred Securities, which purchase the Guarantor
hereby agrees shall benefit the Guarantor, the Guarantor executes and delivers
this Guarantee Agreement for the benefit of the Holders from time to time.

                                    ARTICLE I
                                   DEFINITIONS

         SECTION 1.01 Definitions.

                  (a) Capitalized terms used in this Guarantee Agreement but not
defined in the preamble or recitals above have the respective meanings assigned
to them in this Section 1.01.

                  (b) A term defined anywhere in this Guarantee Agreement has
the same meaning throughout.



                                        1

<PAGE>



                  (c) All references to "the Guarantee Agreement" or "this
Guarantee Agreement" are to this Guarantee Agreement as modified, supplemented
or amended from time to time.

                  (d) All references in this Guarantee Agreement to Articles and
Sections are to Articles and Sections of this Guarantee Agreement unless
otherwise specified.

                  (e) A term defined in the Trust Indenture Act has the same
meaning when used in this Guarantee Agreement unless otherwise defined in this
Guarantee Agreement or unless the context otherwise requires.

                  (f) A reference to the singular includes the plural and vice
versa.

                  "Additional Amounts" has the meaning set forth in the
Indenture.

                  "Affiliate" of any specified Person means any other Person
directly or indirectly controlling or controlled by, or under direct or indirect
common control with, such specified Person. For purposes of this definition,
"control" of a Person shall mean the power to direct the management and policies
of such Person, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise, and the terms "controlling" and
"controlled" shall have meanings correlative to the foregoing.

                  "Business Day" has the meaning set forth in the Indenture.

                  "Commission" means the Securities and Exchange Commission.

                  "Common Securities" means the securities representing common
undivided beneficial interests in the assets of the Issuer and having the terms
set forth in Exhibit C to the Declaration.

                  "Common Stock" means the common stock, _____ par value per
share, of the Guarantor, including associated preferred share purchase rights.

                  "Debentures" means the series of [convertible] unsecured
[junior subordinated] [senior] debentures issued to the Property Trustee by the
Guarantor under the Indenture and entitled the "___% [Convertible] [Junior
Subordinated] [Senior] Debentures due _____."

                  "Declaration" has the meaning set forth in the recitals above.

                  "Distributions" means the periodic distributions and other
payments payable to Holders in accordance with the terms of the Preferred
Securities set forth in Exhibit B to the Declaration.

                  "Dollar" has the meaning set forth in the Indenture.



                                        2

<PAGE>



                  "Event of Default" means a default by the Guarantor on any of
its payment or other obligations under this Guarantee Agreement; provided,
however, that, except with respect to a default in payment of any Guarantee
Payment, any such default shall constitute an Event of Default only if the
Guarantor shall have received notice of such default and shall not have cured
such default within 60 days after receipt of such notice.

                  "Guarantee Payments" means the following payments or
distributions, without duplication, with respect to the Preferred Securities, to
the extent not paid or made by or on behalf of the Issuer: (i) any accumulated
and unpaid Distributions, any Additional Amounts payable with respect to the
Preferred Securities in accordance with the terms thereof and the Redemption
Price, including all accumulated and unpaid Distributions and Additional Amounts
to the date of redemption, with respect to the Preferred Securities called for
redemption by the Issuer but only if and to the extent that in each case the
Guarantor has made a payment to the Property Trustee of principal of, any
premium or interest on or any Additional Amounts with respect to the Debentures
and (ii) upon a voluntary or involuntary dissolution, winding-up or termination
of the Issuer (other than in connection with the distribution of Debentures to
Holders in exchange for Preferred Securities or the redemption of the Preferred
Securities in full upon the maturity or redemption of the Debentures as provided
in the Declaration), the lesser of (a) the aggregate of the liquidation amount
and all accumulated and unpaid Distributions and Additional Amounts on the
Preferred Securities to the date of payment, to the extent the Issuer has funds
on hand legally available therefor, and (b) the amount of assets of the Issuer
remaining available for distribution to Holders in liquidation of the Issuer as
required by applicable law.

                  "Guarantee Trustee" means The Bank of New York, a national
banking association, until a Successor Guarantee Trustee has been appointed and
has accepted such appointment pursuant to the terms of this Guarantee Agreement,
and thereafter means each such Successor Guarantee Trustee.

                  "Holder" means any holder, as registered on the books and
records of the Issuer, of any Preferred Securities; provided, however, that in
determining whether the holders of the requisite percentage of Preferred
Securities have given any request, notice, consent or waiver hereunder, "Holder"
shall not include the Guarantor or any Affiliate of the Guarantor.

                  "Indemnified Person" means the Guarantee Trustee, any
Affiliate of the Guarantee Trustee, and any officers, directors, shareholders,
members, partners, employees, representatives or agents of the Guarantee
Trustee.

                  "Indenture" means the Indenture dated as of _________, ____
between the Guarantor and The Bank of New York, as trustee, as supplemented by
the ________ Supplemental Indenture thereto dated as of _______ __, ____ (the
"Supplemental Indenture"), pursuant to which the Debentures are to be issued to
the Property Trustee.



                                        3

<PAGE>



                  "Majority of Outstanding Preferred Securities" means Holder(s)
of outstanding Preferred Securities, voting together as a single class, who are
the record owners of Preferred Securities representing more than 50% of the
outstanding Preferred Securities.

                  "Officers' Certificate" means, with respect to any Person, a
certificate signed by the Chairman of the Board, the President, any Vice
Chairman of the Board, any Vice President, the chief financial officer, the
Treasurer, any Assistant Treasurer, the Controller, the Secretary or any
Assistant Secretary of such Person, and delivered to the Guarantee Trustee. One
of the officers signing an Officers' Certificate given pursuant to Section 2.04
shall be the principal executive, financial or accounting officer of the
Guarantor. Any Officers' Certificate delivered with respect to compliance with a
condition or covenant provided for in this Guarantee Agreement shall include:

                  (i) a statement that the person making such certificate has
         read such covenant or condition;

                  (ii) a brief statement as to the nature and scope of the
         examination or investigation upon which the statements or opinions
         contained in such certificate are based;

                  (iii) a statement that, in the opinion of such person, he has
         made such examination or investigation as is necessary to enable him to
         express an informed opinion as to whether or not such covenant or
         condition has been complied with; and

                  (iv) a statement as to whether or not, in the opinion of such
         person, such condition or covenant has been complied with.

                  "Person" means any individual, corporation, partnership,
limited liability company, joint venture, incorporated or unincorporated
association, joint stock company, trust, unincorporated organization or
government or other agency or political subdivision thereof or other entity of
any kind.

                  "Preferred Securities" has the meaning set forth in the
recitals above.

                  "Property Trustee" means the Person acting as Property Trustee
under the Declaration.

                  "Redemption Price" means the amount payable on redemption of
the Preferred Securities in accordance with the terms of the Preferred
Securities.

                  "Responsible Officer" means, when used with respect to the
Guarantee Trustee, any officer within the corporate trust department of the
Guarantee Trustee, including any vice president, assistant vice president,
assistant secretary, assistant treasurer, trust officer or any other officer of
the Guarantee Trustee who customarily performs functions similar to those
performed by the Persons who at the time shall be such officers, respectively,
or to whom any corporate trust matter is referred


                                        4

<PAGE>



because of such Person's knowledge of and familiarity with the particular
subject and, in either case, who shall have direct responsibility for the
administration of this Guarantee Agreement.

                  "Successor Guarantee Trustee" means a successor Guarantee
Trustee possessing the qualifications to act as a Guarantee Trustee under
Section 4.01.

                  "Supplemental Indenture" has the meaning specified in the
definition of Indenture.

                  "Trust Indenture Act" means the Trust Indenture Act of 1939,
as amended.


                                   ARTICLE II
                               TRUST INDENTURE ACT

         SECTION 2.01 Trust Indenture Act; Application.

                  (a) This Guarantee Agreement is subject to the provisions of
the Trust Indenture Act that are required to be part of this Guarantee Agreement
and shall, to the extent applicable, be governed by such provisions.

                  (b) If and to the extent that any provision of this Guarantee
Agreement limits, qualifies or conflicts with the duties imposed by Sections 310
to 317, inclusive, of the Trust Indenture Act, such imposed duties shall
control.

                  (c) The application of the Trust Indenture Act to this
Guarantee Agreement shall not affect the nature of the Preferred Securities as
equity securities representing preferred undivided beneficial interests in the
assets of the Issuer.

         SECTION 2.02 Lists of Holders of Preferred Securities.

                  (a) The Guarantor shall provide the Guarantee Trustee (unless
the Guarantee Trustee is the registrar of the Preferred Securities) (i) within
14 days after each record date for payment of Distributions, a list, in such
form as the Guarantee Trustee may reasonably require, of the names and addresses
of the Holders ("List of Holders") as of such date, and (ii) at any other time,
within 30 days of receipt by the Guarantor of a written request for a List of
Holders as of a date no more than 15 days before such List of Holders is given
to the Guarantee Trustee; provided that in each case the Guarantor shall not be
obligated to provide such List of Holders at any time that the List of Holders
does not differ from the most recent List of Holders given to the Guarantee
Trustee by the Guarantor. The Guarantee Trustee shall preserve, in as current a
form as is reasonably practicable, all information contained in the Lists of
Holders given to it; provided that the Guarantee Trustee may destroy any List of
Holders previously given to it on receipt of a new List of Holders.



                                        5

<PAGE>



                  (b) The Guarantee Trustee shall comply with its obligations
under Section 312(b) of the Trust Indenture Act.

         SECTION 2.03 Reports by the Guarantee Trustee.

                  Within 60 days after May 15 of each year, commencing May 15,
____, the Guarantee Trustee shall deliver to the Holders such reports as are
required by Section 313 of the Trust Indenture Act, if any, in the form, in the
manner and at the times provided by Section 313 of the Trust Indenture Act. The
Guarantee Trustee shall also comply with the other requirements of Section 313
of the Trust Indenture Act. A copy of each such report shall, at the time of
such transmission to the Holders, be filed by the Guarantee Trustee with the
Guarantor, with each stock exchange or quotation system upon which any Preferred
Securities are listed or traded (if so listed or traded) and also with the
Commission. The Guarantor agrees to notify the Guarantee Trustee when any
Preferred Securities become listed on any stock exchange or quotation system and
of any delisting thereof.

         SECTION 2.04 Periodic Reports to the Guarantee Trustee.

                  The Guarantor shall provide to the Guarantee Trustee, the
Commission and the Holders, as applicable, such documents, reports and
information (if any) as required by Section 314(a)(1)-(3) of the Trust Indenture
Act and the compliance certificates required by Section 314(a)(4) and (c) of the
Trust Indenture Act, any such certificates to be provided in the form, in the
manner and at the times required by Section 314(a)(4) and (c) of the Trust
Indenture Act (provided that any certificate to be provided pursuant to Section
314(a)(4) of the Trust Indenture Act shall be provided within 120 days of the
end of each fiscal year of the Issuer). Delivery of such reports, information
and documents to the Guarantee Trustee is for informational purposes only and
the Guarantee Trustee's receipt of such shall not constitute constructive notice
of any information contained therein, including the Guarantor's compliance with
any of its covenants hereunder (as to which the Guarantee Trustee is entitled to
rely exclusively on Officers' Certificates or on certificates provided pursuant
to this Section 2.04).

         SECTION 2.05 Evidence of Compliance with Conditions Precedent.

                  The Guarantor shall provide to the Guarantee Trustee such
evidence of compliance with any conditions precedent, if any, provided for in
this Guarantee Agreement which relate to any of the matters set forth in Section
314(c) of the Trust Indenture Act. Any certificate or opinion required to be
given by an officer pursuant to Section 314(c) may be given in the form of an
Officers' Certificate.

         SECTION 2.06 Events of Default; Waiver.

                  (a) The Holders of a Majority of Outstanding Preferred
Securities may, by vote, on behalf of the Holders, waive any past Event of
Default and its consequences. Upon such waiver, any such Event of Default shall
cease to exist, and any Event of Default arising therefrom shall be


                                        6

<PAGE>



deemed to have been cured, for every purpose of this Guarantee Agreement, but no
such waiver shall extend to any subsequent or other default or Event of Default,
or impair any right consequent thereon.

                  (b) The right of any Holder to receive payment of the
Guarantee Payments in accordance with this Guarantee Agreement, or to institute
suit for the enforcement of any such payment, shall not be impaired without the
consent of each such Holder.

         SECTION 2.07 Disclosure of Information.

                  The disclosure of information as to the names and addresses of
the Holders in accordance with Section 312 of the Trust Indenture Act,
regardless of the source from which such information was derived, shall not be
deemed to be a violation of any existing law, or any law hereafter enacted which
does not specifically refer to Section 312 of the Trust Indenture Act, nor shall
the Guarantee Trustee be held accountable by reason of mailing any material
pursuant to a request made under Section 312(b) of the Trust Indenture Act.

         SECTION 2.08 Conflicting Interest.

                  (a) The Declaration shall be deemed to be specifically
described in this Guarantee Agreement for the purposes of clause (i) of the
first proviso contained in Section 310(b) of the Trust Indenture Act.

                  (b) The Guarantee Trustee shall comply with its obligations
under Sections 310(b) and 311 of the Trust Indenture Act.


                                   ARTICLE III
               POWERS, DUTIES AND RIGHTS OF THE GUARANTEE TRUSTEE

         SECTION 3.01 Powers and Duties of the Guarantee Trustee.

                  (a) This Guarantee Agreement shall be held by the Guarantee
Trustee in trust for the benefit of the Holders. The Guarantee Trustee shall not
transfer its right, title and interest in this Guarantee Agreement to any Person
except a Successor Guarantee Trustee on acceptance by such Successor Guarantee
Trustee of its appointment to act as Guarantee Trustee or to a Holder exercising
his or her rights pursuant to Section 5.04(iv). The right, title and interest of
the Guarantee Trustee to this Guarantee Agreement shall vest automatically in
each Person who may hereafter be appointed as Guarantee Trustee in accordance
with Article IV. Such vesting and cessation of title shall be effective whether
or not conveyancing documents have been executed and delivered.

                  (b) If an Event of Default has occurred and is continuing, the
Guarantee Trustee shall enforce this Guarantee Agreement for the benefit of the
Holders.


                                        7

<PAGE>



                  (c) This Guarantee Agreement and all moneys received by the
Guarantee Trustee in respect of the Guarantee Payments will not be subject to
any right, charge, security interest, lien or claim of any kind in favor of, or
for the benefit of, the Guarantee Trustee or its agents or their creditors.

                  (d) The Guarantee Trustee shall, within 90 days after the
occurrence of an Event of Default actually known to a Responsible Officer of the
Guarantee Trustee, transmit by mail, first class postage prepaid, to the
Holders, as their names and addresses appear upon the List of Holders, notice of
all such Events of Default, unless such defaults shall have been cured before
the giving of such notice; provided that the Guarantee Trustee shall be
protected in withholding such notice if and so long as the board of directors,
the executive committee or a trust committee of directors and/or Responsible
Officers of the Guarantee Trustee in good faith determines that the withholding
of such notice is in the interests of the Holders. The Guarantee Trustee shall
not be deemed to have knowledge of any Event of Default except any Event of
Default as to which the Guarantee Trustee shall have received written notice or
a Responsible Officer charged with the administration of this Guarantee
Agreement shall have obtained written notice of such Event of Default.

                  (e) The Guarantee Trustee shall continue to serve as a trustee
until a Successor Guarantee Trustee has been appointed and accepted that
appointment in accordance with Article IV.

         SECTION 3.02 Certain Rights and Duties of the Guarantee Trustee.

                  (a) The Guarantee Trustee, before the occurrence of an Event
of Default and after the curing or waiving of all Events of Default that may
have occurred, shall undertake to perform only such duties as are specifically
set forth in this Guarantee Agreement, and no implied covenants shall be read
into this Guarantee Agreement against the Guarantee Trustee. In case an Event of
Default has occurred (that has not been cured or waived pursuant to Section
2.06), the Guarantee Trustee shall exercise such of the rights and powers vested
in it by this Guarantee Agreement, and use the same degree of care and skill in
its exercise thereof, as a prudent person would exercise or use under the
circumstances in the conduct of his own affairs.

                  (b) No provision of this Guarantee Agreement shall be
construed to relieve the Guarantee Trustee from liability for its own negligent
action, its own negligent failure to act or its own willful misconduct, except
that:

                  (i) prior to the occurrence of an Event of Default and after
         the curing or waiving of all such Events of Default that may have
         occurred:

                           (A) the duties and obligations of the Guarantee
                  Trustee shall be determined solely by the express provisions
                  of this Guarantee Agreement, and the Guarantee Trustee shall
                  not be liable except for the performance of such duties and
                  obligations as are specifically set forth in this Guarantee
                  Agreement, and no implied


                                        8

<PAGE>



                  covenants or obligations shall be read into this Guarantee
                  Agreement against the Guarantee Trustee; and

                           (B) in the absence of bad faith on the part of the
                  Guarantee Trustee, the Guarantee Trustee may conclusively
                  rely, as to the truth of the statements and the correctness of
                  the opinions expressed therein, upon any certificates or
                  opinions furnished to the Guarantee Trustee and conforming to
                  the requirements of this Guarantee Agreement; provided,
                  however, that in the case of any such certificates or opinions
                  that by any provision hereof or the Trust Indenture Act are
                  specifically required to be furnished to the Guarantee
                  Trustee, the Guarantee Trustee shall be under a duty to
                  examine the same to determine whether or not they conform to
                  the requirements of this Guarantee Agreement or the Trust
                  Indenture Act, as the case may be;

                  (ii) the Guarantee Trustee shall not be liable for any error
         of judgment made in good faith by a Responsible Officer of the
         Guarantee Trustee, unless it shall be proved that the Guarantee Trustee
         was negligent in ascertaining the pertinent facts upon which such
         judgment was made;

                  (iii) the Guarantee Trustee shall not be liable with respect
         to any action taken or omitted to be taken by it in good faith in
         accordance with the direction of the Holders of a Majority of
         Outstanding Preferred Securities relating to the time, method and place
         of conducting any proceeding for any remedy available to the Guarantee
         Trustee, or exercising any trust or power conferred upon the Guarantee
         Trustee under this Guarantee Agreement; and

                  (iv) no provision of this Guarantee Agreement shall require
         the Guarantee Trustee to expend or risk its own funds or otherwise
         incur personal financial liability in the performance of any of its
         duties or in the exercise of any of its rights or powers, if it shall
         have reasonable grounds for believing that the repayment of such funds
         or liability is not reasonably assured to it under the terms of this
         Guarantee Agreement or adequate indemnity against such risk or
         liability is not reasonably assured to it.

         (c) Subject to the provisions of Section 3.02(a) and (b):

                  (i) whenever in the administration of this Guarantee
         Agreement, the Guarantee Trustee shall deem it desirable that a matter
         be proved or established prior to taking, suffering or omitting any
         action hereunder, the Guarantee Trustee (unless other evidence is
         herein specifically prescribed) may, in the absence of bad faith on its
         part, request and rely upon an Officers' Certificate, which, upon
         receipt of such request, shall be promptly delivered by the Guarantor;



                                        9

<PAGE>



                  (ii) the Guarantee Trustee (A) may consult with counsel (which
         may be counsel to the Guarantor or any of its Affiliates and may
         include any of its employees) selected by it in good faith and with due
         care and the written advice or opinion of such counsel with respect to
         legal matters shall be full and complete authorization and protection
         in respect of any action taken, suffered or omitted by it hereunder in
         good faith and in reliance thereon and in accordance with such advice
         and opinion and (B) shall have the right at any time to seek
         instructions concerning the administration of this Guarantee Agreement
         from any court of competent jurisdiction;

                  (iii) the Guarantee Trustee may execute any of the trusts or
         powers hereunder or perform any duties hereunder either directly or by
         or through agents or attorneys, and the Guarantee Trustee shall not be
         responsible for any misconduct or negligence on the part of any agent
         or attorney appointed by it in good faith and with due care;

                  (iv) the Guarantee Trustee shall be under no obligation to
         exercise any of the rights or powers vested in it by this Guarantee
         Agreement at the request or direction of any Holder, unless such Holder
         shall have offered to the Guarantee Trustee security and indemnity
         satisfactory to the Guarantee Trustee against the costs, expenses
         (including attorneys' fees and expenses) and liabilities that might be
         incurred by it in complying with such request or direction; provided
         that nothing contained in this clause (iv) shall relieve the Guarantee
         Trustee of the obligation, upon the occurrence of an Event of Default
         (which has not been cured or waived) to exercise such of the rights and
         powers vested in it by this Guarantee Agreement, and to use the same
         degree of care and skill in this exercise as a prudent person would
         exercise or use under the circumstances in the conduct of his own
         affairs; and

                  (v) any action taken by the Guarantee Trustee or its agents
         hereunder shall bind the Holders, and the signature of the Guarantee
         Trustee or its agents alone shall be sufficient and effective to
         perform any such action; and no third party shall be required to
         inquire as to the authority of the Guarantee Trustee to so act, or as
         to its compliance with any of the terms and provisions of this
         Guarantee Agreement, both of which shall be conclusively evidenced by
         the Guarantee Trustee's or its agent's taking such action.

         SECTION 3.03 Not Responsible for Recitals or Issuance of Guarantee.

                  The recitals contained in this Guarantee Agreement shall be
taken as the statements of the Guarantor, and the Guarantee Trustee does not
assume any responsibility for their correctness. The Guarantee Trustee makes no
representations as to the validity or sufficiency of this Guarantee Agreement.



                                       10

<PAGE>



         SECTION 3.04 The Guarantee Trustee May Own Preferred Securities.

                  The Guarantee Trustee, in its individual or any other
capacity, may become the owner or pledgee of Preferred Securities and may
otherwise deal with the Guarantor with the same rights it would have if it were
not the Guarantee Trustee.

         SECTION 3.05 Moneys Received by the Guarantee Trustee to Be Held in
                      Trust Without Interest.

                  All moneys received by the Guarantee Trustee in respect of
Guarantee Payments shall, until used or applied as herein provided, be held in
trust for the purposes for which they were received, but need not be segregated
from other funds except to the extent required by law. The Guarantee Trustee
shall be under no liability for interest on any moneys received by it hereunder
except such as it may agree in writing to pay thereon.

         SECTION 3.06 Compensation and Expenses of Guarantee Trustee.

                  The Guarantor covenants and agrees to pay to the Guarantee
Trustee from time to time, and the Guarantee Trustee shall be entitled to, such
compensation as the Guarantor and the Guarantee Trustee shall from time to time
agree in writing (which shall not be limited by any provision of law in regard
to the compensation of a Guarantee Trustee of an express trust) for all services
rendered by it in the exercise and performance of any of the powers and duties
hereunder of the Guarantee Trustee, and the Guarantor will pay or reimburse the
Guarantee Trustee upon its request for all reasonable expenses, disbursements
and advances incurred or made by the Guarantee Trustee in accordance with any of
the provisions of this Guarantee Agreement (including the reasonable
compensation and the reasonable expenses and disbursements of its counsel and of
all persons not regularly in its employ) except any such expense, disbursement
or advance as may arise from its negligence or bad faith. The Guarantor also
covenants to indemnify each of the Guarantee Trustee or any predecessor
Guarantee Trustee and their officers, agents, directors and employees for, and
to hold them harmless against, any and all loss, liability, damage, claim or
expense including taxes (other than taxes based upon, measured by or determined
by the income, profit, franchise or doing business of the Guarantee Trustee)
incurred without negligence or bad faith on the part of the Guarantee Trustee
and arising out of or in connection with the acceptance or administration of
this trust, including the reasonable costs and expenses of defending itself
against any claim (whether asserted by the Guarantor, any Holder or any other
Person) of liability in the premises. The provisions of this Section 3.06 shall
survive the termination of this Guarantee Agreement and resignation or removal
of the Guarantee Trustee.



                                       11

<PAGE>



                                   ARTICLE IV
                                GUARANTEE TRUSTEE

         SECTION 4.01 Qualifications.

                  There shall at all times be a Guarantee Trustee that shall:

                  (i) not be an Affiliate of the Guarantor; and

                  (ii) be a national banking association or corporation
         organized and doing business under the laws of the United States of
         America or any State or Territory thereof or of the District of
         Columbia, or a corporation or Person permitted by the Commission to act
         as an institutional trustee under the Trust Indenture Act, authorized
         under such laws to exercise corporate trust powers, having a combined
         capital and surplus of at least $50,000,000, and subject to supervision
         or examination by Federal, State, Territorial or District of Columbia
         authority. If such corporation publishes reports of condition at least
         annually, pursuant to law or to the requirements of the supervising or
         examining authority referred to above, then for the purposes of this
         clause (ii), the combined capital and surplus of such corporation shall
         be deemed to be its combined capital and surplus as set forth in its
         most recent report of condition so published.

                  If at any time the Guarantee Trustee shall cease to satisfy
the requirements of clauses (i) and (ii) above, the Guarantee Trustee shall
immediately resign in the manner and with the effect set out in Section 4.02. If
the Guarantee Trustee has or shall acquire any "conflicting interest" within the
meaning of Section 310(b) of the Trust Indenture Act, the Guarantee Trustee and
the Guarantor shall in all respects comply with the provisions of Section 310(b)
of the Trust Indenture Act.

         SECTION 4.02 Appointment, Removal and Resignation of the Guarantee
Trustee.

                  (a) Subject to Section 4.02(b), the Guarantee Trustee may be
appointed or removed without cause at any time by the Guarantor.

                  (b) The Guarantee Trustee shall not be removed in accordance
with Section 4.02(a) until a Successor Guarantee Trustee possessing the
qualifications to act as Guarantee Trustee under Section 4.01 has been appointed
and has accepted such appointment by written instrument executed by such
Successor Guarantee Trustee and delivered to the Guarantor and the Guarantee
Trustee being removed.

                  (c) The Guarantee Trustee appointed to office shall hold
office until its successor shall have been appointed or until its removal or
resignation.

                  (d) The Guarantee Trustee may resign from office (without need
for prior or subsequent accounting) by an instrument (a "Resignation Request")
in writing signed by the


                                       12

<PAGE>



Guarantee Trustee and delivered to the Guarantor, which resignation shall take
effect upon such delivery or upon such later date as is specified therein;
provided, however, that no such resignation of the Guarantee Trustee shall be
effective until a Successor Guarantee Trustee possessing the qualifications to
act as Guarantee Trustee under Section 4.01 has been appointed and has accepted
such appointment by instrument executed by such Successor Guarantee Trustee and
delivered to the Guarantor and the resigning Guarantee Trustee.

                  (e) If no Successor Guarantee Trustee shall have been
appointed and accepted appointment as provided in this Section 4.02 within 60
days after delivery to the Guarantor of a Resignation Request, the resigning
Guarantee Trustee may petition any court of competent jurisdiction for
appointment of a Successor Guarantee Trustee. Such court may thereupon after
such notice, if any, as it may deem proper, appoint a Successor Guarantee
Trustee.

                                    ARTICLE V
                                    GUARANTEE

         SECTION 5.01 Guarantee.

                  The Guarantor irrevocably and unconditionally agrees to pay in
full to the Holders the Guarantee Payments (without duplication of amounts
theretofore paid by the Issuer), as and when due, regardless of any defense,
right of set-off or counterclaim which the Issuer may have or assert. The
Guarantor's obligation to make a Guarantee Payment may be satisfied by direct
payment of the required amounts by the Guarantor to the Holders or to the
Guarantee Trustee for remittance to the Holders or by causing the Issuer to pay
such amounts to the Holders.

         SECTION 5.02 Waiver of Notice.

                  The Guarantor hereby waives notice of acceptance of this
Guarantee Agreement and of any liability to which it applies or may apply,
presentment, demand for payment, any right to require a proceeding first against
the Issuer or any other Person before proceeding against the Guarantor, protest,
notice of nonpayment, notice of dishonor, notice of redemption and all other
notices and demands. Notwithstanding anything to the contrary herein, the
Guarantor retains all of its rights under the Indenture to extend the interest
payment period on the Debentures and the Guarantor shall not be obligated
hereunder to make any Guarantee Payment during any Extended Interest Payment
Period (as defined in the Supplemental Indenture) with respect to the
Distributions on the Preferred Securities.

         SECTION 5.03 Obligations Not Affected.

                  The obligations, covenants, agreements and duties of the
Guarantor under this Guarantee Agreement shall in no way be affected or impaired
by reason of the happening from time to time of any of the following:



                                       13

<PAGE>



                  (a) the release or waiver, by operation of law or otherwise,
         of the performance or observance by the Issuer of any express or
         implied agreement, covenant, term or condition relating to the
         Preferred Securities to be performed or observed by the Issuer;

                  (b) the extension of time for the payment by the Issuer of all
         or any portion of the Distributions (other than an extension of time
         for payment of Distributions that result from any Extended Interest
         Payment Period), Redemption Price, Liquidation Distribution (as defined
         in the Declaration) or any other sums payable under the terms of the
         Preferred Securities or the extension of time for the performance of
         any other obligation under, arising out of, or in connection with, the
         Preferred Securities (other than an extension of time for payment of
         Distributions that result from any Extended Interest Payment Period);

                  (c) any failure, omission, delay or lack of diligence on the
         part of the Guarantee Trustee or the Holders to enforce, assert or
         exercise any right, privilege, power or remedy conferred on the
         Guarantee Trustee or the Holders pursuant to the terms hereof or of the
         Preferred Securities, respectively, or any action on the part of the
         Issuer granting indulgence or extension of any kind;

                  (d) the voluntary or involuntary liquidation, dissolution,
         sale of any collateral, receivership, insolvency, bankruptcy,
         assignment for the benefit of creditors, reorganization, arrangement,
         composition or readjustment of debt of, or other similar proceedings
         affecting, the Issuer or any of the assets of the Issuer;

                  (e) any invalidity of, or defect or deficiency in, the
         Preferred Securities;

                  (f) the settlement or compromise of any obligation guaranteed
         hereby or hereby incurred; or

                  (g) any other circumstance whatsoever that might otherwise
         constitute a legal or equitable discharge or defense of a guarantor, it
         being the intent of this Section 5.03 that the obligations of the
         Guarantor with respect to the Guarantee Payments shall be absolute and
         unconditional under any and all circumstances.

                  There shall be no obligation of the Guarantee Trustee or the
Holders to give notice to, or obtain consent of, the Guarantor with respect to
the happening of any of the foregoing.

         SECTION 5.04 Enforcement of Guarantee.

                  The Guarantor and the Guarantee Trustee expressly acknowledge
and agree that (i) this Guarantee Agreement will be deposited with the Guarantee
Trustee to be held for the benefit of the Holders; (ii) the Guarantee Trustee
has the right to enforce this Guarantee Agreement on behalf of the Holders;
(iii) Holders representing not less than a Majority of Outstanding Preferred
Securities have the right to direct the time, method and place of conducting any
proceeding for any


                                       14

<PAGE>



remedy available to the Guarantee Trustee in respect of this Guarantee Agreement
or exercising any trust or other power conferred upon the Guarantee Trustee
under this Guarantee Agreement; and (iv) if the Guarantee Trustee fails to
enforce this Guarantee Agreement as provided in clauses (ii) and (iii) above,
any Holder may institute a legal proceeding directly against the Guarantor to
enforce its rights under this Guarantee Agreement, without first instituting a
legal proceeding against the Issuer, the Guarantee Trustee or any other Person.
Notwithstanding the foregoing, if the Guarantor has failed to make a Guarantee
Payment, a Holder may directly institute a proceeding against the Guarantor for
enforcement of this Guarantee Agreement for such payment without first
instituting a legal proceeding against the Issuer, the Guarantee Trustee or any
other Person.

         SECTION 5.05 Guarantee of Payment.

                  This Guarantee Agreement creates a guarantee of payment and
not merely of collection. This Guarantee Agreement will not be discharged except
by payment of the Guarantee Payments in full (without duplication of amounts
theretofore paid by the Issuer) or upon the distribution of the Debentures to
the Holders as provided in the Declaration.

         SECTION 5.06 Subrogation.

                  The Guarantor shall be subrogated to all (if any) rights of
the Holders against the Issuer in respect of any amounts paid to the Holders by
the Guarantor under this Guarantee Agreement; provided, however, that the
Guarantor shall not (except to the extent required by mandatory provisions of
law) be entitled to enforce or exercise any rights which it may acquire by way
of subrogation or any indemnity, reimbursement or other agreement, in all cases
as a result of payment under this Guarantee Agreement, if, at the time of any
such payment, any amounts are due and unpaid under this Guarantee Agreement. If
any amount shall be paid to the Guarantor in violation of the preceding
sentence, the Guarantor agrees to hold such amount in trust for the Holders and
to pay over such amount to the Holders or to the Guarantee Trustee for
remittance to the Holders.

         SECTION 5.07 Independent Obligations.

                  The Guarantor acknowledges that its obligations hereunder are
independent of the obligations of the Issuer with respect to the Preferred
Securities and that the Guarantor shall be liable as principal and as debtor
hereunder to make Guarantee Payments pursuant to the terms of this Guarantee
Agreement notwithstanding the occurrence of any event referred to in subsections
(a) through (g), inclusive, of Section 5.03 hereof.



                                       15

<PAGE>



                                   ARTICLE VI
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

         SECTION 6.01 Limitation of Transactions.

                  So long as any Preferred Securities remain outstanding, the
Guarantor shall not (1) make any payment of principal, interest or premium, if
any, on or repay, repurchase or redeem any debt securities that rank junior to
the Debentures in the right of payment issued by the Guarantor, or (2) make any
guarantee payments with respect to any guarantee by the Guarantor of any
securities of any of its subsidiaries if such guarantee ranks junior to the
Debentures in right of payment or (3) declare or pay any dividends or
distributions on, or redeem, purchase, acquire or make a liquidation payment
with respect to, any of the Guarantor's capital stock, except for or as a result
of (a) dividends or distributions in, or options, warrants or rights to
subscribe for or purchase, the Common Stock; (b) any declaration of a dividend
in connection with the implementation of a shareholder's rights plan, or the
issuance of shares under any such plan in the future, or the redemption or
repurchase of any such rights pursuant thereto; (c) a reclassification of the
Guarantor's capital stock solely into shares of one or more classes or series of
the Guarantor's capital stock or the exchange or conversion of one class or
series of the Guarantor's capital stock for or into another class or series of
the Guarantor's capital stock; (d) the purchase of fractional interests in
shares of the Guarantor's capital stock pursuant to the conversion or exchange
provisions of such capital stock or the security being converted or exchanged;
and (e) the purchase of the Guarantor's common stock in connection with the
Guarantor's normal course issuer bid-purchases for the satisfaction by the
Guarantor of its obligations under any benefit plans for the Guarantor and the
Guarantor's subsidiaries' directors, officers or employees or under any of the
Guarantor's dividend reinvestment plans, if at such time (i) the Guarantor shall
be in default with respect to its Guarantee Payments or other payment
obligations hereunder, (ii) there shall have occurred and be continuing any
trust enforcement event under the Declaration or (iii) the Guarantor shall have
given notice of its election of an Extended Interest Payment Period and such
period, or any extension thereof, is continuing. In addition, so long as any
Preferred Securities remain outstanding, the Guarantor (i) will remain the sole
direct or indirect owner of all of the outstanding Common Securities and shall
not cause or permit the Common Securities to be transferred except to the extent
such transfer is permitted under Section [9.01] of the Declaration; provided
that any permitted successor of the Guarantor under the Indenture may succeed to
the Guarantor's direct or indirect ownership of the Common Securities, [(ii)
will cause the holder of the Common Securities to satisfy the requirements of
Section 4.03 of the Declaration] and (iii) will use reasonable efforts to cause
the Issuer to continue to be treated as a grantor trust for United States
federal income tax purposes, except in connection with a distribution of
Debentures as provided in the Declaration.



                                       16

<PAGE>



         [SECTION 6.02 Subordination.

                  This Guarantee Agreement will constitute an unsecured
obligation of the Guarantor and will rank (i) subordinate and junior in right of
payment to all other liabilities of the Guarantor and any guarantees of the
Guarantor relating to such liabilities, except in each case those made pari
passu or subordinate by their terms, and (ii) senior to all capital stock
[(other than the most senior preferred stock issued from time to time, if any,
by the Guarantor, which preferred stock will rank pari passu with this Guarantee
Agreement)] and to any guarantee now or hereafter entered into by the Guarantor
in respect of any of its capital stock [(other than the most senior preferred
stock issued by the guarantor)] now or hereafter issued by the Guarantor. The
Guarantor's obligations under this Guarantee Agreement will rank pari passu with
respect to obligations under other securities (other than capital stock) the
Guarantor may issue from time to time and other guarantee agreements which it
may enter into from time to time to the extent that (i) such agreements shall
provide for comparable guarantees by the Guarantor of payment on preferred
securities issued by other trusts, partnerships or other entities affiliated
with the Guarantor that are financing vehicles of the Guarantor and (ii) the
debentures or other evidences of indebtedness of the Guarantor relating to such
preferred securities are junior subordinated, unsecured indebtedness of the
Guarantor. The obligations of the Guarantor under this Guarantee Agreement shall
rank pari passu with the Guarantee Agreement, dated as of        , between the
Guarantor and the Guarantee Trustee.]

                                   ARTICLE VII
                                   TERMINATION

         SECTION 7.01 Termination.

                  This Guarantee Agreement shall terminate and be of no further
force and effect (i) upon full payment of the Redemption Price of all Preferred
Securities, (ii) upon the distribution of Debentures [, or any securities in to
which such Debentures are convertible,] to Holders and holders of Common
Securities in exchange for all of the Preferred Securities and Common Securities
or (iii) upon full payment of the amounts payable in accordance with the
Declaration upon liquidation of the Issuer. Notwithstanding the foregoing, this
Guarantee Agreement will continue to be effective or will be reinstated, as the
case may be, if at any time any Holder must restore payment of any sums paid
with respect to the Preferred Securities or under this Guarantee Agreement.

                                  ARTICLE VIII
                    LIMITATION OF LIABILITY; INDEMNIFICATION

         SECTION 8.01 Exculpation.

                  (a) No Indemnified Person shall be liable, responsible or
accountable in damages or otherwise to the Guarantor or any Holder for any loss,
damage or claim incurred by reason of any act or omission performed or omitted
by such Indemnified Person in good faith in accordance with this Guarantee
Agreement and in a manner such Indemnified Person reasonably believed to be
within


                                       17

<PAGE>



the scope of the authority conferred on such Indemnified Person by this
Guarantee Agreement or by law, except that an Indemnified Person shall be liable
for any such loss, damage or claim incurred by reason of such Indemnified
Person's negligence or willful misconduct with respect to such acts or
omissions.

                  (b) An Indemnified Person shall be fully protected in relying
in good faith upon the records of the Guarantor and upon such information,
opinions, reports or statements presented to the Guarantor by any Person as to
matters the Indemnified Person reasonably believes are within such other
Person's professional or expert competence and who has been selected with
reasonable care by or on behalf of the Guarantor, including information,
opinions, reports or statements as to the value and amount of the assets,
liabilities, profits, losses or any other facts pertinent to the existence and
amount of assets from which Distributions to Holders might properly be paid.

         SECTION 8.02 Indemnification.

                  To the fullest extent permitted by applicable law, the
Guarantor shall indemnify and hold harmless each Indemnified Person from and
against any loss, damage or claim incurred by such Indemnified Person by reason
of any act or omission performed or omitted by such Indemnified Person in good
faith in accordance with this Guarantee Agreement and in a manner such
Indemnified Person reasonably believed to be within the scope of authority
conferred on such Indemnified Person by this Guarantee Agreement, except that no
Indemnified Person shall be entitled to be indemnified in respect of any loss,
damage or claim incurred by such Indemnified Person by reason of negligence or
willful misconduct with respect to such acts or omissions.

         SECTION 8.03 Survive Termination.

                  The provisions of Sections 8.01 and 8.02 shall survive the
termination of this Guarantee Agreement or the resignation or removal of the
Guarantee Trustee.

                                   ARTICLE IX
                                  MISCELLANEOUS

         SECTION 9.01 Successors and Assigns.

                  All guarantees and agreements contained in this Guarantee
Agreement shall bind the successors, assignees, receivers, trustees and
representatives of the Guarantor and shall inure to the benefit of the Guarantee
Trustee and the Holders then outstanding. Except in connection with a
consolidation, merger or sale involving the Guarantor that is permitted under
Article X of the Indenture, the Guarantor shall not assign its obligations
hereunder.



                                       18

<PAGE>



         SECTION 9.02 Amendments.

                  Except with respect to any changes which do not adversely
affect the rights of Holders in any material respect (in which case no consent
of Holders will be required), this Guarantee Agreement may only be amended with
the prior approval of the Guarantor, the Guarantee Trustee and the Holders of
not less than a Majority of Outstanding Preferred Securities. The provisions of
Section [12.02] of the Declaration concerning meetings of Holders shall apply to
the giving of such approval.

         SECTION 9.03 Notices.

                  Any notice, request or other communication required or
permitted to be given hereunder shall be in writing, in English, duly signed by
the party giving such notice, and delivered, telecopied or mailed by first class
mail as follows:

                  (a) if given to the Guarantor, to the address set forth below
         or such other address as the Guarantor may give notice of to the
         Holders:

                  Valero Energy Corporation
                  One Valero Way
                  San Antonio, Texas 78249
                  Attention: General Counsel

                  (b) if given to the Guarantee Trustee, to the address set
         forth below or such other address as the Guarantee Trustee may give
         notice of to the Holders:

                  The Bank of New York

                  ---------------------------

                  ---------------------------

                  ---------------------------
                  Attention:

                  (c) if given to any Holder, at the address set forth on the
         books and records of the Issuer.

                  All notices hereunder shall be deemed to have been given when
(i) received in person, (ii) telecopied with receipt confirmed, or (iii) mailed
by first class mail, postage prepaid, when received, except that if a notice or
other document is refused delivery or cannot be delivered because of a changed
address of which no notice was given, such notice or other document shall be
deemed to have been delivered on the date of such refusal or inability to
deliver.



                                       19

<PAGE>



         SECTION 9.04 Genders.

                  The masculine, feminine and neuter genders used herein shall
include the masculine, feminine and neuter genders.

         SECTION 9.05 Benefit.

                  This Guarantee Agreement is solely for the benefit of the
Guarantee Trustee and the Holders and, subject to Section 3.01(a), is not
separately transferable from the Preferred Securities.

         SECTION 9.06 Governing Law.

                  THIS GUARANTEE AGREEMENT SHALL BE GOVERNED BY AND CONSTRUED
AND INTERPRETED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK (WITHOUT
REGARD TO PRINCIPLES OF CONFLICTS OF LAWS).

         SECTION 9.07 Counterparts.

                  This Guarantee Agreement may be executed in counterparts, each
of which shall be an original; but such counterparts shall together constitute
one and the same instrument.

         SECTION 9.08 [Exercise of Overallotment Option.

                  If and to the extent that Preferred Securities are issued by
the Issuer upon exercise of the overallotment option referred to in the first
WHEREAS clause, the Guarantor agrees to give prompt notice thereof to the
Guarantee Trustee but the failure to give such notice shall not relieve the
Guarantor of any of its obligations hereunder.]

         SECTION 9.09 Limited Liability.

                  Neither the Guarantee Trustee nor the Holders, in their
capacities as such, shall be personally liable for any liabilities or
obligations of the Guarantor arising out of this Guarantee Agreement. The
parties further hereby agree that the Holders, in their capacities as such,
shall be entitled to the same limitation of personal liability extended to the
stockholders of private corporations for profit organized under the General
Corporation Law of the State of Delaware.




                                       20

<PAGE>


         THIS GUARANTEE AGREEMENT is executed as of the day and year first above
written.

                                          VALERO ENERGY CORPORATION


                                          By:
                                             -----------------------------------
                                             Name:
                                             Title:


                                          THE BANK OF NEW YORK
                                               as Guarantee Trustee


                                          By:
                                             -----------------------------------
                                             Name:
                                             Title:




                                       21