EXHIBIT 4.3.24


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THIS WARRANT AND ANY SECURITIES  ACQUIRED UPON THE EXERCISE OF THIS WARRANT HAVE
NOT BEEN  REGISTERED  UNDER:  (A) THE  SECURITIES  ACT OF 1933,  AS AMENDED,  IN
RELIANCE UPON THE EXEMPTIONS FROM  REGISTRATION  PROVIDED IN SECTIONS 3 AND 4 OF
SUCH  ACT  AND/OR  REGULATIONS  D  PROMULGATED  THEREUNDER;  OR  (B)  ANY  STATE
SECURITIES  LAWS  IN  RELIANCE  UPON  APPLICABLE  EXEMPTIONS  THEREUNDER.  THESE
SECURITIES  MUST BE ACQUIRED FOR INVESTMENT ONLY FOR THE ACCOUNT OF THE INVESTOR
AND MAY NOT BE SOLD OR  TRANSFERRED  IN THE  ABSENCE OF  REGISTRATION  UNDER THE
SECURITIES  LAWS OR AN OPINION OF COUNSEL  ACCEPTABLE TO THE  CORPORATION OR ITS
REPRESENTATIVES  THAT  SUCH  SALE  OR  TRANSFER  WOULD  NOT  VIOLATE  APPLICABLE
SECURITIES LAWS OR REGULATIONS.
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Warrant No. ___                                             To Purchase ________
                                                          Shares of Common Stock
                                                              ($0.001 par value)

                      CLASS "AI" WARRANT TO PURCHASE SHARES
                               OF COMMON STOCK OF
                                  PROBEX CORP.
                            (A DELAWARE CORPORATION)

                        PURCHASE PRICE PER SHARE: $1.243



         THIS CERTIFIES that, for value received,



is the registered owner and is entitled,  subject to the terms and conditions of
this Warrant,  until the Expiration Date (as set forth in Section 2 hereof),  to
purchase  the number of shares of common  stock,  $0.001 par value (the  "Common
Stock"),   of  Probex  Corp.  (the  "Corporation")  set  forth  above  from  the
Corporation  at the  purchase  price set forth  above.  The  number of shares of
Common  Stock which may be received  upon the  exercise of this  Warrant and the
price to be paid for each share of Common Stock are subject to  adjustment  from
time to time as hereinafter set forth.

1. Exercise of Warrant.  Subject to the provisions  hereof,  this Warrant may be
exercised  in whole or in part until the  Expiration  Date,  by delivery of this
Warrant to the  Corporation  with the exercise form duly executed and payment of
the purchase price (in cash or by certified or bank cashier's check made payable
to the order of the Corporation) for each share purchased.

2. Expiration Date of Warrant.  Subject to the provisions  hereof,  this Warrant
shall expire five (5) years from the date that the outstanding  principal amount
and accrued but unpaid interest due under that certain  Secured  Promissory Note
(the "Note"), dated as of February 20, 2001, made by the Corporation in favor of
___________ is repaid in full.

3.  Corporation's  Covenants as to Common  Stock.  Shares  deliverable  upon the
exercise of this Warrant shall, at delivery,  be fully paid and  non-assessable,
free from  taxes,  liens,  and  charges  with  respect  to their  purchase.  The
Corporation  shall at all times reserve and hold available  sufficient shares of

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Class "AI" Warrant No. ____
Page 2


Common  Stock to satisfy  all  conversion  and  purchase  rights of  outstanding
convertible securities, options and warrants.

4. Method of Exercise;  Fractional  Shares.  The purchase rights  represented by
this Warrant are  exercisable at the option of the registered  owner in whole at
any time, or in part, from time to time,  within the period specified in Section
2 hereof;  provided,  however,  that purchase  rights are not  exercisable  with
respect to a fraction of a share of Common Stock.  In lieu of issuing a fraction
of a share  remaining  after  exercise  of this  Warrant  as to all full  shares
covered hereby,  the Corporation shall either (1) pay therefor cash equal to the
same fraction of the then current  Warrant  purchase  price per share or, at its
option, (2) issue scrip for the fraction,  in registered or bearer form approved
by the board of directors of the Corporation,  which shall entitle the holder to
receive a  certificate  for a full share of Common  Stock on  surrender of scrip
aggregating a full share.  Scrip may become void after a reasonable  period (but
not less than six months after the expiration  date of this Warrant)  determined
by the board of directors and specified in the scrip. In case of the exercise of
this Warrant for less than all the shares  purchasable,  the  Corporation  shall
cancel this Warrant and execute and deliver a new Warrant of like tenor and date
for the balance of the shares purchasable hereunder.

5.  Adjustment of Exercise  Price. If from the date hereof until two years after
the date of repayment of the Note in full, the Corporation shall (i) issue, (ii)
enter into any  binding  agreement  to issue,  or (iii)  commence  any public or
private  offering  for the  issuance  of,  shares of Common  Stock,  warrants to
purchase  shares  of  Common  Stock  or  debt or  equity  securities  which  are
convertible  into shares of Common  Stock,  in an  aggregate  amount of at least
100,000 shares of Common Stock  (excluding any options to purchase  Common Stock
issued pursuant to any employee stock option plan of the  Corporation),  and the
issuance,  exercise or conversion  price (the  "Issuance  Price") of such Common
Stock is less than $1.243 per share,  then the exercise price per share pursuant
to this Warrant shall be adjusted (and the Corporation  shall,  after occurrence
of any event requiring such adjustment, notify the holder of this Warrant of the
adjustment) so that the exercise price shall be equal to the Issuance Price. For
purposes of this section,  a public or private  offering shall be deemed to have
commenced if the there is substantial agreement as to the material terms of such
offering.

6.  Redemption.  The  Corporation  has no  redemption  rights  pursuant  to this
Warrant.

7.  Limited  Rights of Owner.  This  Warrant  does not  entitle the owner to any
voting rights or other rights as a  shareholder  of the  Corporation,  or to any
other rights  whatsoever  except the rights expressed  herein.  No dividends are
payable  or will  accrue on this  Warrant or the  shares  purchasable  hereunder
until, and except to the extent that, this Warrant is exercised.

8.  Exchange  for Other  Denominations.  This  Warrant is  exchangeable,  on its
surrender by the registered owner to the  Corporation,  for new Warrants of like
tenor and date representing in the aggregate the right to purchase the number of
shares purchasable hereunder in denominations designated by the registered owner
at the time of surrender.

9. Transfer.  Except as otherwise provided, this Warrant is transferable only on
the books of the  Corporation by the registered  owner in person or by attorney,
on surrender of this Warrant,  properly endorsed.  However, because this Warrant
has not been  registered  under the  Securities  Act of 1933,  as  amended  (the
"Securities Act"), and applicable state securities laws, this Warrant may not be
sold or transferred in the absence of an effective registration of it under such
Act and all other applicable securities laws or an opinion of counsel acceptable
to the Corporation or its  representatives  that such sale or transfer would not
violate  applicable  securities laws or regulations.  Any Common Stock purchased
upon the exercise of this Warrant shall also be subject to the same restrictions
on transfer  and will contain the same or similar  transfer  legend found on the
face of this Warrant.

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Class "AI" Warrant No. ____
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10.      Registration Rights.

         (1) Each time that the Corporation  proposes for any reason to register
any of its Common Stock under the Securities Act in connection with the proposed
offer and sale of its Common  Stock for money  either for its own  account or on
behalf  of any other  security  holder  ("Proposed  Registration"),  other  than
pursuant to a registration  statement on Form S-4, S-8 or any successor thereto,
the Corporation shall promptly give written notice of such Proposed Registration
to the holder  hereof and shall  offer such  holder  hereof the right to request
inclusion of the shares  issued or issuable upon the exercise of this Warrant in
the Proposed Registration.

         (2) The holder hereof shall have ten (10) days from the receipt of such
notice to deliver to the Corporation a written request  specifying the number of
shares such holder hereof  intends to sell and the holder's  intended  method of
disposition.

         (3) In the event that the Proposed  Registration by the Corporation is,
in whole or in part, an underwritten  public offering,  the Corporation shall so
advise the holder hereof as part of the written notice given pursuant to Section
10(1),  and any request  under  Section  10(2) must  specify  that the shares of
Common Stock be included in the underwriting on the same terms and conditions as
the shares of Common Stock, if any,  otherwise  being sold through  underwriters
under such registration.

         (4) Upon receipt of a written  request  pursuant to Section 10(2),  the
Corporation shall promptly use its commercially  reasonable efforts to cause all
such shares of Common Stock held by the holder hereof to be registered under the
Securities Act (and included in any related  qualifications  under blue sky laws
or other  compliance),  to the extent required to permit the sale or disposition
as set forth in the Proposed Registration.

         (5) In the event that the offering is to be an  underwritten  offering,
the holder  hereof  proposing to  distribute  its shares of Common Stock through
such underwritten  offering agrees to enter into an underwriting  agreement with
the  underwriter  or  underwriters   selected  for  such   underwriting  by  the
Corporation.

         (6) Notwithstanding the foregoing,  if in its good faith judgment,  the
managing underwriter determines and advises in writing that the inclusion of all
shares of Common Stock issued or issuable with respect to this Warrant  proposed
to be included in the  underwritten  public  offering,  together  with any other
issued and outstanding shares of Common Stock proposed to be included therein by
holders  other than the  holder  hereof,  would  interfere  with the  successful
marketing of such  securities,  then the number of such shares to be included in
such underwritten  public offering shall be reduced, on a pro-rata basis (except
only those shares held by holders  that have the benefit of any priority  rights
previously  granted such holders),  based upon the number of shares held by each
holder,  including the holder hereof; provided that, in connection with any such
public  offering,  if the  managing  underwriter  reasonably  and in good  faith
recommends,  which recommendation and supporting reasoning shall be delivered in
writing to the holders,  that no amount of shares,  including shares held by the
holder hereof, should be included in the underwritten public offering,  then the
Corporation  shall not be  required  to include  any such  shares in such public
offering.

11.  Recognition of Registered Owner.  Prior to due presentment for registration
of transfer of this Warrant,  the Corporation may treat the registered  owner as
the person  exclusively  entitled to receive  notices and  otherwise to exercise
rights hereunder.

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Class "AI" Warrant No. ____
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12. Effect of Stock Split,  etc. If the Corporation,  by stock dividend,  split,
reverse split,  reclassification of shares, or otherwise, changes as a whole the
outstanding Common Stock into a different number or class of shares, then:

         (1) the number and class of shares so changed  shall,  for the purposes
of this Warrant, replace the shares outstanding immediately prior to the change;
and

         (2) the  Warrant  purchase  price in  effect,  and the number of shares
purchasable  under this  Warrant,  immediately  prior to the date upon which the
change becomes effective,  shall be  proportionately  adjusted (the price to the
nearest cent).

13. Effect of Merger,  etc. If the Corporation  consolidates with or merges into
another  corporation,  the  registered  owner  shall  thereafter  be entitled on
exercise to purchase,  with  respect to each share of Common  Stock  purchasable
hereunder immediately before the consolidation or merger becomes effective,  the
securities or other consideration to which a holder of one share of Common Stock
is entitled in the  consolidation or merger to assure that all the provisions of
this Warrant shall thereafter be applicable,  as nearly as reasonable may be, to
any  securities  or other  consideration  so  deliverable  on  exercise  of this
Warrant.  The  Corporation  shall  not  consolidate  or merge  unless,  prior to
consummation,  the successor corporation (if other than the Corporation) assumes
the obligations of this Section 13 by written instrument  executed and mailed to
the  registered  owner  at  the  address  of  the  owner  on  the  books  of the
Corporation.  A sale or  lease of all or  substantially  all the  assets  of the
Corporation  for  consideration  (apart  from  the  assumption  of  obligations)
consisting  primarily  of  securities  is a  consolidation  or  merger  for  the
foregoing purposes.

14. Notice of Adjustment.  On the happening of an event  requiring an adjustment
of the Warrant purchase price or shares purchasable  hereunder,  the Corporation
shall forthwith give written notice to the registered owner stating the adjusted
Warrant  purchase price and the adjusted  number and kind of securities or other
property  purchasable  hereunder  resulting  from the event and setting forth in
reasonable  detail  the  method  of  calculation  and the facts  upon  which the
calculation is based. The board of directors of the Corporation,  acting in good
faith, shall determine the calculation. Irrespective of any adjustment or change
in the Warrant purchase price or the number of shares  purchasable under this or
any other Warrant of like tenor, the Warrants  theretofore and thereafter issued
may continue to express the Warrant  purchase  price per share and the number of
shares  purchasable  as were  expressed  in the Warrant when  initially  issued;
provided,  however,  the Corporation  may, in its sole  discretion,  request the
holder of this  Warrant to  exchange  this  Warrant  for a warrant of like tenor
reflecting  such  adjustment  or change  provided for in this  Warrant,  and the
holder of this Warrant agrees to cooperate  with the  Corporation to effect such
exchange.

15. Notice and Effect of  Dissolution,  etc. In case a voluntary or  involuntary
dissolution,  liquidation,  or  winding  up of the  Corporation  (other  than in
connection with a consolidation or merger covered by Section 13 above) is at any
time proposed, the Corporation shall give at least 10 days written notice to the
registered  owner prior to the record date as of which  holders of Common  Stock
will  be  entitled  to  receive  distributions  as  a  result  of  the  proposed
transaction. Such notice shall contain: (1) the date on which the transaction is
to take place;  (2) the record date as of which  holders of Common Stock will be
entitled to receive  distributions as a result of the  transaction;  (3) a brief
description of the transaction;  (4) a brief description of the distributions to
be made to holders of Common  Stock as a result of the  transaction;  and (5) an
estimate of the fair value of the distributions. On the date of the transaction,
if it actually occurs, this Warrant and all rights hereunder shall terminate.

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Class "AI" Warrant No. ____
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16. Method of Giving Notice;  Extent  Required.  Notices shall be given by first
class mail, postage prepaid, addressed to the registered owner at the address of
the owner  appearing  in the  records of the  Corporation.  No notice to warrant
holders is required except as specified in Sections 5, 10, 14 and 15.

17. Access to Information.  The  Corporation  will provide an opportunity to any
registered  owner  of  this  Warrant  to  ask  questions  of  management  of the
Corporation  and to obtain  information to the extent the  Corporation  has made
such information  publicly available prior to any exercise of the owner's rights
to purchase  Common Stock under this Warrant.  Requests for  information and any
other questions concerning the business and affairs of the Corporation should be
directed to the Vice President of Investor  Relations of the  Corporation at its
main offices.


                  [REMAINDER OF PAGE LEFT BLANK INTENTIONALLY]

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Class "AI" Warrant No. ____
Page 6


         IN WITNESS  WHEREOF,  the  Corporation  has caused  this  Warrant to be
executed  and  delivered  by its duly  authorized  officer  as of the 1st day of
October, 2001.



                                         PROBEX CORP.


                                         By: ________________________________
                                         Name:    Bruce A. Hall
                                         Title:   Senior Vice President & Chief
                                                  Financial Officer



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Class "AI" Warrant No. ____
Page 7


                                  TRANSFER FORM



     For value received, the undersigned hereby sells, assigns, and transfers to


Name__________________________________

Address_______________________________



this Warrant and irrevocably  appoints  ______________________________  attorney
(with full power of  substitution)  to transfer this Warrant on the books of the
Corporation.

Date:

_________________________________

                                 _______________________________________________
                                (Please sign exactly as name appears on Warrant)

                                Taxpayer ID No. ________________________

In the presence of              Signature guaranteed by

_______________________________ ________________________________________________


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Class "AI" Warrant No. ____
Page 8

                                  EXERCISE FORM



         The undersigned hereby: (1) irrevocably subscribes for ________________
shares of your Common Stock  pursuant to this Warrant,  and encloses  payment of
$____________________  therefor;  (2) requests that a certificate for the shares
be issued in the name of the undersigned and delivered to the undersigned at the
address  below;  and (3) if  such  number  of  shares  is not all of the  shares
purchasable  hereunder,  that a new Warrant of like tenor for the balance of the
remaining shares purchasable  hereunder be issued in the name of the undersigned
and delivered to the undersigned at the address below.

Date:

____________________________

                                _____________________________________________
                               (Please sign exactly as name appears on Warrant)

                                Address:_________________________________

                                        _________________________________


                                Taxpayer ID No.___________________________