SIXTH AMENDMENT AGREEMENT

This SIXTH AMENDMENT AGREEMENT (this “Amendment”) is made as of the 1st day of
June, 2011 among:

(a) CORE MOLDING TECHNOLOGIES, INC., a Delaware corporation (“Core Molding”);

(b) CORECOMPOSITES DE MEXICO, S. DE R.L. DE C.V., a sociedad de responsabilidad
limitada de capital variable organized under the laws of Mexico (“Core Mexico”
and, together with Core Molding, collectively, “Borrowers” and, individually,
each a “Borrower”);

(c) the Lenders, as defined in the Credit Agreement, as hereinafter defined; and

(d) KEYBANK NATIONAL ASSOCIATION, as the lead arranger, sole book runner and
administrative agent for the Lenders under the Credit Agreement (“Agent”).

WHEREAS, Borrowers, Agent and the Lenders are parties to that certain Credit
Agreement, dated as of December 9, 2008, that provides, among other things, for
loans and letters of credit aggregating Thirty-Four Million Eleven Thousand
Fifty-Six and 15/100 Dollars ($34,011,056.15), all upon certain terms and
conditions (as amended and as the same may from time to time be further amended,
restated or otherwise modified, the “Credit Agreement”);

WHEREAS, Borrowers, Agent and the Lenders desire to amend the Credit Agreement
to modify certain provisions thereof and add certain provisions thereto;

WHEREAS, each capitalized term used herein and defined in the Credit Agreement,
but not otherwise defined herein, shall have the meaning given such term in the
Credit Agreement; and

WHEREAS, unless otherwise specifically provided herein, the provisions of the
Credit Agreement revised herein are amended effective as of the date of this
Amendment;

NOW, THEREFORE, in consideration of the premises and of the mutual covenants
herein and for other valuable consideration, the receipt and sufficiency of
which is hereby acknowledged, Borrowers, Agent and the Lenders agree as follows:

1. Amendment to Definitions in the Credit Agreement. Section 1.1 of the Credit
Agreement is hereby amended to delete the definitions of “Applicable Margin”,
“Base Rate Loan”, “Commitment”, “Commitment Period”, “Consolidated EBITDA”,
“Consolidated Fixed Charges”, “Consolidated Unfunded Capital Expenditures”,
“Daily LIBOR Loan”, “Daily LIBOR Rate”, “Loan”, “Note”, and “Required Lenders”
therefrom and to insert in place thereof, respectively, the following:

“Applicable Margin” means (a) one hundred seventy-five (175.00) basis points for
Eurodollar Loans, (b) one hundred seventy-five (175.00) basis points for Daily
LIBOR Loans, and (c) zero (0.00) basis points for Base Rate Loans.

“Base Rate Loan” means a Revolving Loan described in Section 2.2(a) hereof, a
portion of the Term Loan described in Section 2.3 hereof, a Capex Draw Loan
described in Section 2.4(a) hereof, a portion of the Capex Term Loan described
in Section 2.4(b) hereof, an Expansion Revolving Loan described in
Section 2.4A(a) hereof, or the Mexican Loan described in Section 2.5 hereof,
that shall be denominated in Dollars and on which a Borrower shall pay interest
at a rate based on the Derived Base Rate.

“Commitment” means the obligation hereunder of the Lenders, during the
applicable Commitment Periods, (a) to make Revolving Loans and to participate in
the issuance of Letters of Credit and Swing Loans pursuant to the Revolving
Credit Commitment, (b) to make the Term Loan pursuant to the Term Loan
Commitment (which Term Loan has been repaid prior to the Sixth Amendment
Effective Date), (c) to make Capex Loans pursuant to the Capex Commitment,
(d) to make Expansion Revolving Loans pursuant to the Expansion Revolving Credit
Commitment, (e) to make the Mexican Loan pursuant to the Mexican Loan
Commitment, and (f) to participate in the issuance of the IDRB Letter of Credit;
up to the Total Commitment Amount.

“Commitment Period” means (a) with respect to the Revolving Credit Commitment,
the period from the Closing Date to May 31, 2013, (b) with respect to the
Expansion Revolving Credit Commitment, the period from the Sixth Amendment
Effective Date to May 31, 2013, and (c) with respect to the IDRB Letter of
Credit Commitment, the period from the Closing Date to April 17, 2014, or, in
the case of each subpart (a), (b), and (c), such earlier date on which the
Commitment shall have been terminated pursuant to Article VIII hereof.

“Consolidated EBITDA” means, for any period, as determined on a Consolidated
basis and in accordance with GAAP, (a) Consolidated Net Earnings for such period
plus, without duplication, the aggregate amounts deducted in determining such
Consolidated Net Earnings in respect of (i) Consolidated Interest Expense,
(ii) Consolidated Income Tax Expense, (iii) Consolidated Depreciation and
Amortization Charges, (iv) reasonable non-recurring non-cash losses not incurred
in the ordinary course of business, (v) non-cash compensation expenses
recognized under Statement of Financial Accounting Standards 123R in connection
with Core Molding’s equity incentive stock option plan and restricted stock
grants, and (vi) non-cash post-retirement expenses minus retirement benefits
paid in cash; minus, (b) to the extent included in Consolidated Net Earnings for
such period, non-recurring gains not incurred in the ordinary course of
business.

“Consolidated Fixed Charges” means, for any period, on a Consolidated basis and
in accordance with GAAP, the aggregate, without duplication, of (a) Consolidated
Interest Expense (including, without limitation, the “imputed interest” portion
of Capitalized Lease Obligations, synthetic leases and asset securitizations, if
any, but excluding any measure of ineffectiveness related to interest rate swaps
and amortization of loan origination and issuance costs), (b) Consolidated
Income Tax Expense, (c) scheduled principal payments of long-term Consolidated
Funded Indebtedness (other than scheduled principal payments of the Mexican Loan
that were prepaid by Core Molding or any of its Subsidiaries one year (or
longer) prior to the due date of such principal payment), (d) Capital
Distributions, and (e) Consolidated Unfunded Capital Expenditures; provided
that, for the purposes of calculating the Fixed Charge Coverage Ratio,
Consolidated Unfunded Capital Expenditures shall exclude project costs related
to the Matamoras Expansion Project that are incurred on or before December 31,
2012, up to an aggregate amount not to exceed the total of (i) Fourteen Million
Five Hundred Thousand Dollars ($14,500,000), minus (ii) the outstanding balance
on the Expansion Revolving Credit Exposure.

“Consolidated Unfunded Capital Expenditures” means, for any period, all
additions to fixed assets of the Companies not funded with (a) long-term
Indebtedness, (b) Capitalized Lease Obligations, or (c) the Expansion Revolving
Loans.

“Daily LIBOR Loan” means a Revolving Loan described in Section 2.2(a) hereof, an
Expansion Revolving Loan described in Section 2.4A(a) hereof, or the Mexican
Loan described in Section 2.5 hereof, that shall be denominated in Dollars and
on which a Borrower shall pay interest at a rate based on the Derived Daily
LIBOR Rate.

“Daily LIBOR Rate” means, for any Daily Interest Period:

(a) with respect to a Daily LIBOR Loan that is a Revolving Loan, an Expansion
Revolving Loan, or a Swing Loan, a per annum rate of interest (rounded upwards,
if necessary, to the nearest 1/16th of 1%) at which, determined by Agent in
accordance with its usual procedures (which determination shall be conclusive
absent manifest error) as of approximately 11:00 A.M. (London time) two Business
Days prior to the beginning of such Daily Interest Period, Dollar deposits in
immediately available funds in an amount comparable to such Loan and with a
maturity of one day are offered to the prime banks by leading banks in the
London interbank market; and

(b) with respect to a Daily LIBOR Loan that is the Mexican Loan, a rate per
annum equal to a per annum the rate of interest, as of approximately 11:00 A.M.
(London time) two Business Days prior to such date as the rate in the London
interbank market for Dollar deposits in immediately available funds in an amount
comparable to such Loan and with a maturity of one day are offered to the prime
banks by leading banks in the London interbank market.

“Loan” means (a) a Revolving Loan, a Swing Loan, the Term Loan, a Capex Loan or
an Expansion Revolving Loan granted to Core Molding by the Lenders in accordance
with Section 2.2(a), 2.2(c), 2.3, 2.4 or 2.4A(a) hereof, or (b) the Mexican Loan
granted to Core Mexico by the Lenders in accordance with Section 2.5 hereof.

“Note” means a Revolving Credit Note, the Swing Line Note, the Term Note, a
Capex Note, an Expansion Revolving Credit Note or the Mexican Note, or any other
promissory note delivered pursuant to this Agreement.

“Required Lenders” means the holders of more than fifty percent (50%) of the sum
of:

(a) (i) during the Commitment Period applicable to the Revolving Credit
Commitment, the Maximum Revolving Amount, or (ii) after such Commitment Period,
the Revolving Credit Exposure;

(b) the principal outstanding under the Term Loan;

(c) (i) during the Commitment Period applicable to the Capex Draw Commitment,
the Maximum Capex Draw Amount, or (ii) after such Commitment Period, the
principal outstanding under the Capex Term Loan Commitment;

(d) (i) during the Commitment Period applicable to the Expansion Revolving
Credit Commitment, the Maximum Expansion Revolving Amount, or (ii) after such
Commitment Period, the Expansion Revolving Credit Exposure;

(e) (i) during the Commitment Period applicable to the Mexican Loan Commitment,
the Maximum Mexican Draw Amount, or (ii) after such Commitment Period, the
principal outstanding under the Mexican Loan Commitment; and

(f) the IDRB Letter of Credit Exposure.

2. Additions to Definitions. Section 1.1 of the Credit Agreement is hereby
amended to add the following new definitions thereto:

“Matamoros Expansion Project” means the expansion of a manufacturing plant in
Matamoros, Mexico, at the location set forth on Schedule 3(b) hereto.

“Maximum Expansion Revolving Amount” means Ten Million Dollars ($10,000,000).

“Expansion Revolving Credit Commitment” means the obligations hereunder of the
Lenders, during the applicable Commitment Period, to make Expansion Revolving
Loans, up to an aggregate principal amount outstanding at any time equal to the
Maximum Expansion Revolving Amount.

“Expansion Revolving Credit Exposure” means, at any time, the aggregate
principal amount of all Expansion Revolving Loans outstanding.

“Expansion Revolving Credit Note” means an Expansion Revolving Credit Note, in
the form of the attached Exhibit M, executed and delivered pursuant to
Section 2.8(f) hereof.

“Expansion Revolving Loan” means a Loan granted to Core Molding by the Lenders
in accordance with Section 2.4A(a) hereof.

“Sixth Amendment Effective Date” means June 1, 2011.

3. Amendment to Amount and Nature of Credit Provisions. Section 2.1 of the
Credit Agreement is hereby amended to delete subsection (c) therefrom and to
insert in place thereof the following:

(c) The Loans may be made as Revolving Loans as described in Section 2.2(a)
hereof, as the Term Loan as described in Section 2.3 hereof, as Capex Draw Loans
as described in Section 2.4(a) hereof, as the Capex Term Loan as described in
Section 2.4(b) hereof, as Expansion Revolving Loans as described in
Section 2.4A(a) hereof, as the Mexican Loan as described in Section 2.5 hereof,
and as Swing Loans as described in Section 2.2(c) hereof; Letters of Credit may
be issued in accordance with Section 2.2(b) hereof; and the IDRB Letter of
Credit has been issued in accordance with Section 2.6 hereof.

4. Amendment to Amount and Terms of Credit Provisions. Article II of the Credit
Agreement is hereby amended to add the following new Section 2.4A thereto:

Section 2.4A. Expansion Revolving Credit Commitment.

(a) Expansion Revolving Loans. Subject to the terms and conditions of this
Agreement, during the Commitment Period applicable to the Expansion Revolving
Credit Commitment, the Lenders shall make an Expansion Revolving Loan or
Expansion Revolving Loans to Core Molding in such amount or amounts as
Administrative Borrower, through an Authorized Officer, may from time to time
request, but in the aggregate principal amount not exceeding at any time the
Maximum Expansion Revolving Amount. Core Molding shall have the option, subject
to the terms and conditions set forth herein, to borrow Expansion Revolving
Loans, maturing on the last day of the Commitment Period applicable to the
Expansion Revolving Credit Commitment, by means of any combination of Base Rate
Loans or Daily LIBOR Loans.

(b) Optional Conversion of Expansion Revolving Loans. Notwithstanding anything
herein to the contrary, so long as no Default or Event of Default shall then
exist, Borrower shall have the option to convert the Expansion Revolving Loans
to a term loan on or before the last day of the Commitment Period applicable to
the Expansion Revolving Credit Commitment. Such term loan shall have terms and
conditions, and be subject to documentation, that is in each case acceptable to
Agent and the Lenders.

5. Amendment to IDRB Letter of Credit Provisions. Section 2.6 of the Credit
Agreement is hereby amended to delete subsection (c)(i) therefrom and to insert
in place thereof the following:

(c) IDRB Letter of Credit Fees. With respect to the IDRB Letter of Credit, Core
Molding agrees to:

(i) pay to Agent, for the pro rata benefit of the Lenders, a non-refundable
letter of credit fee from the Closing Date through the last day of the
Commitment Period applicable to the IDRB Letter of Credit, which shall be paid
monthly in arrears, on each Regularly Scheduled Payment Date, at a rate per
annum equal to (A) one hundred seventy-five (175.00) basis points, multiplied by
(B) the IDRB Letter of Credit Commitment, as such amount is reduced on a
quarterly basis in accordance with the terms of the IDRB Documents;

6. Amendment to Interest. Section 2.7 of the Credit Agreement is hereby amended
to delete subsection (f) therefrom and to insert in place thereof the following
new subsection (f), and to add the following new subsection (j) at the end
thereof:

(f) Mexican Loan.

(i) Base Rate Loan. Core Mexico shall pay interest on the unpaid principal
amount of a Mexican Loan that is a Base Rate Loan outstanding from time to time,
from the date thereof until paid, at the Derived Base Rate from time to time in
effect. Interest on the Mexican Loan shall be payable on each Regularly
Scheduled Payment Date thereafter and at the maturity thereof; provided that the
Mexican Loan shall bear interest at the Derived Base Rate if required by
Article III hereof.

(ii) Daily LIBOR Loans. Core Mexico shall pay interest on the unpaid principal
amount of each Mexican Loan that is a Daily LIBOR Loan outstanding from time to
time, from the date thereof until paid, at the Derived Daily LIBOR Rate from
time to time in effect. Interest on the Mexican Loan shall be payable on each
Regularly Scheduled Payment Date thereafter and at the maturity thereof.

(j) Expansion Revolving Loans.

(i) Base Rate Loan. Core Molding shall pay interest on the unpaid principal
amount of an Expansion Revolving Loan that is a Base Rate Loan outstanding from
time to time, from the date thereof until paid at the Derived Base Rate from
time to time in effect. Interest on such Base Rate Loan shall be payable,
commencing July 1, 2011, and continuing on each Regularly Scheduled Payment Date
thereafter and at the maturity thereof.

(ii) Daily LIBOR Loans. Core Molding shall pay interest on the unpaid principal
amount of each Expansion Revolving Loan that is a Daily LIBOR Loan outstanding
from time to time, from the date thereof until paid, at the Derived Daily LIBOR
Rate from time to time in effect. Interest on such Daily LIBOR Loan shall be
payable, commencing July 1, 2011, and continuing on each Regularly Scheduled
Payment Date thereafter and at the maturity thereof.

7. Addition to Evidence of Indebtedness Provisions. Section 2.8 of the Credit
Agreement is hereby amended to add the following new subsection (f) thereto:

(f) Expansion Revolving Loan. Upon the request of a Lender, to evidence the
obligation of Core Molding to repay the Expansion Revolving Loans made by such
Lender and to pay interest thereon, Core Molding shall execute an Expansion
Revolving Credit Note, payable to the order of such Lender in the principal
amount of its Commitment Percentage of the Expansion Revolving Credit
Commitment; provided that the failure of a Lender to request an Expansion
Revolving Credit Note shall in no way detract from Core Molding’s obligations to
such Lender hereunder.

8. Addition to Commitment and Other Fee Provisions. Section 2.12 of the Credit
Agreement is hereby amended to add the following new subsection (f) thereto:

(f) Commitment Fee for Expansion Revolving Loans. Core Molding shall pay to
Agent, for the ratable account of the Lenders, as a consideration for the
Expansion Revolving Credit Commitment, a commitment fee from the Sixth Amendment
Effective Date to and including the last day of the Commitment Period applicable
to the Expansion Revolving Credit Commitment, payable quarterly, at a rate per
annum equal to (i) the Applicable Commitment Fee Rate in effect on the payment
date, multiplied by (ii) (A) the average daily Maximum Expansion Revolving
Amount in effect during such quarter, minus (B) the average daily Expansion
Revolving Credit Exposure during such quarter. The commitment fee for the
Expansion Revolving Loans shall be payable in arrears, on July 1, 2011 and
continuing on the first day of each October, January, April, and July
thereafter, and on the last day of the Commitment Period applicable to the
Expansion Revolving Credit Commitment.

9. Amendment to Prepayment Provisions. Section 2.14 of the Credit Agreement is
hereby amended to delete subsection (f)(i) therefrom and to insert in place
thereof the following new subsection (f)(i), and to add the following new
subpart (g) at the end thereof:

(f) Application of Mandatory Prepayments. Each Mandatory Prepayment required to
be made pursuant to Section 2.14(e) hereof shall be applied as follows:

(i) if such Mandatory Prepayment is payable by Core Molding, (A) first, to the
Term Loan (to the payments of principal in the inverse order of maturities),
with such payment first to be applied to the outstanding Base Rate Loans and
then to the outstanding Eurodollar Loans, (B) second, as applicable, to the
Capex Draw Loans and the Capex Term Loan (to the payments of principal in the
inverse order of maturities), with such payment first to be applied to the
outstanding Base Rate Loans and then to the outstanding Eurodollar Loans,
(C) third, to the Expansion Revolving Loans, with such payment first to be
applied to the outstanding Base Rate Loans and then to the outstanding Daily
LIBOR Loans, and (C) fourth, to Revolving Loans, with such payment first to be
applied to the outstanding Base Rate Loans and then to the outstanding Daily
LIBOR Loans; and

(g) Expansion Revolving Credit Exposure. If, at any time, the Expansion
Revolving Credit Exposure shall exceed the Expansion Revolving Credit
Commitment, Core Molding shall, as promptly as practicable, but in no event
later than the next Business Day, pay an aggregate principal amount of the
Expansion Revolving Loans sufficient to bring the Expansion Revolving Credit
Exposure within the Expansion Revolving Credit Commitment.

10. Deletion of Capital Expenditures Financial Covenant. Section 5.7 of the
Credit Agreement is hereby amended to delete subsection (c) in its entirety.

11. Amendment to Use of Proceeds Provisions. Article V of the Credit Agreement
is hereby amended to delete Section 5.18 therefrom and to insert in place
thereof the following:

Section 5.18. Use of Proceeds. Borrowers’ use of the proceeds of (a) the Capex
Loans and the Mexican Loan shall be for the Mexican Project, (b) the Expansion
Revolving Loans shall be for capital expenditures for the Matamoros Expansion
Project, and (c) the Revolving Loans and the Term Loan shall be for working
capital and other general corporate purposes of the Companies, and for the
refinancing of existing Indebtedness.

12. Addition to Application of Proceeds Provisions. Section 8.8 of the Credit
Agreement is hereby amended to add the following new subsection (vi) thereto:

(vi) with respect to payments received in connection with the Expansion
Revolving Credit Commitment, to the Expansion Revolving Loans;

13. Amendment to Schedule 1. The Credit Agreement is hereby amended to delete
Schedule 1 (Commitments of Lenders) therefrom and to insert in place thereof a
new Schedule 1 in the form of Schedule 1 hereto.

14. Addition to Exhibits. The Credit Agreement is hereby amended to add Exhibit
M (Form of Expansion Revolving Credit Note) thereto in the form of Exhibit M
hereto.

15. Closing Deliveries. Concurrently with the execution of this Amendment, Core
Molding shall:

(a) execute and deliver to Agent a replacement Revolving Credit Note, a
replacement Capex Note, and an Expansion Revolving Credit Note;

(b) deliver to Agent certified copies of the resolutions of the board of
directors of Core Molding evidencing approval of the execution and delivery of
this Amendment and the execution of any other Loan Documents and Related
Writings required in connection therewith;

(c) pay a renewal fee to Agent, for the benefit of the Lenders, in the amount of
One Thousand Dollars ($1,000);

(d) cause each Guarantor of Payment to execute the attached Guarantor
Acknowledgment and Agreement; and

(e) pay all legal fees and expenses of Agent in connection with this Amendment
and any other Loan Documents.

16. Representations and Warranties. Borrowers hereby represent and warrant to
Agent and the Lenders that (a) Borrowers have the legal power and authority to
execute and deliver this Amendment; (b) the officers executing this Amendment
have been duly authorized to execute and deliver the same and bind Borrowers
with respect to the provisions hereof; (c) the execution and delivery hereof by
Borrowers and the performance and observance by Borrowers of the provisions
hereof do not violate or conflict with the Organizational Documents of Borrowers
or any law applicable to Borrowers or result in a breach of any provision of or
constitute a default under any other agreement, instrument or document binding
upon or enforceable against Borrowers; (d) no Default or Event of Default
exists, nor will any occur immediately after the execution and delivery of this
Amendment or by the performance or observance of any provision hereof; (e) each
of the representations and warranties contained in the Loan Documents is true
and correct in all material respects as of the Sixth Amendment Effective Date as
if made on the Sixth Amendment Effective Date, except to the extent that any
such representation or warranty expressly states that it relates to an earlier
date (in which case such representation or warranty is true and correct in all
material respects as of such earlier date); (f) Borrowers are not aware of any
claim or offset against, or defense or counterclaim to, Borrowers’ obligations
or liabilities under the Credit Agreement or any Related Writing; and (g) this
Amendment constitutes a valid and binding obligation of Borrowers in every
respect, enforceable in accordance with its terms.

17. Waiver and Release. Borrowers, by signing below, hereby waive and release
Agent, and each of the Lenders, and their respective directors, officers,
employees, attorneys, affiliates and subsidiaries, from any and all claims,
offsets, defenses and counterclaims of which Borrowers are aware, such waiver
and release being with full knowledge and understanding of the circumstances and
effect thereof and after having consulted legal counsel with respect thereto.

18. References to Credit Agreement and Ratification. Each reference to the
Credit Agreement that is made in the Credit Agreement or any other Related
Writing shall hereafter be construed as a reference to the Credit Agreement as
amended hereby. Except as herein otherwise specifically provided, all terms and
provisions of the Credit Agreement are confirmed and ratified and shall remain
in full force and effect and be unaffected hereby. This Amendment is a Loan
Document.

19. Counterparts. This Amendment may be executed in any number of counterparts,
by different parties hereto in separate counterparts and by facsimile signature,
each of which, when so executed and delivered, shall be deemed to be an original
and all of which taken together shall constitute but one and the same agreement.

20. Headings. The headings, captions and arrangements used in this Amendment are
for convenience only and shall not affect the interpretation of this Amendment.

21. Severability. Any term or provision of this Amendment held by a court of
competent jurisdiction to be invalid or unenforceable shall not impair or
invalidate the remainder of this Amendment and the effect thereof shall be
confined to the term or provision so held to be invalid or unenforceable.

22. Governing Law. The rights and obligations of all parties hereto shall be
governed by the laws of the State of Ohio, without regard to principles of
conflicts of laws.

[Remainder of page intentionally left blank.]

JURY TRIAL WAIVER. BORROWERS, AGENT AND THE LENDERS, TO THE EXTENT PERMITTED BY
LAW, EACH HEREBY WAIVES ANY RIGHT TO HAVE A JURY PARTICIPATE IN RESOLVING ANY
DISPUTE, WHETHER SOUNDING IN CONTRACT, TORT OR OTHERWISE, AMONG BORROWERS, AGENT
AND THE LENDERS, OR ANY THEREOF, ARISING OUT OF, IN CONNECTION WITH, RELATED TO,
OR INCIDENTAL TO THE RELATIONSHIP ESTABLISHED AMONG THEM IN CONNECTION WITH THIS
AMENDMENT OR ANY NOTE OR OTHER INSTRUMENT, DOCUMENT OR AGREEMENT EXECUTED OR
DELIVERED IN CONNECTION HEREWITH OR THE TRANSACTIONS RELATED THERETO. THIS
WAIVER SHALL NOT IN ANY WAY AFFECT, WAIVE, LIMIT, AMEND OR MODIFY THE ABILITY OF
AGENT OR THE LENDERS TO PURSUE REMEDIES PURSUANT TO ANY CONFESSION OF JUDGMENT
OR COGNOVIT PROVISION CONTAINED IN ANY NOTE OR OTHER INSTRUMENT, DOCUMENT OR
AGREEMENT AMONG BORROWERS, AGENT AND THE LENDERS.

IN WITNESS WHEREOF, the parties have executed and delivered this Amendment in
Columbus, Ohio as of the date first set forth above.

 
CORE MOLDING TECHNOLOGIES, INC.
By: /s/ Herman F. Dick, Jr.
Name: Herman F. Dick, Jr.
Title: Vice President & CFO
 
CORECOMPOSITES DE MEXICO, S. DE R.L. DE C.V.
By: /s/ Herman F. Dick, Jr.
Name: Herman F. Dick, Jr.
Title: Attorney in Fact
KEYBANK NATIONAL ASSOCIATION,
as Agent and as a Lender
By: /s/ Roger D. Campbell
Name: Roger D. Campbell
Title: SVP

GUARANTOR ACKNOWLEDGMENT AND AGREEMENT

The undersigned consent and agree to and acknowledge the terms of the foregoing
Sixth Amendment Agreement dated as of June 1, 2011. The undersigned further
agree that the obligations of the undersigned pursuant to the Guaranty of
Payment executed by the undersigned are hereby ratified and shall remain in full
force and effect and be unaffected hereby.

The undersigned hereby waive and release Agent and the Lenders and their
respective directors, officers, employees, attorneys, affiliates and
subsidiaries from any and all claims, offsets, defenses and counterclaims of any
kind or nature, absolute and contingent, of which the undersigned are aware or
should be aware, such waiver and release being with full knowledge and
understanding of the circumstances and effect thereof and after having consulted
legal counsel with respect thereto.

JURY TRIAL WAIVER. THE UNDERSIGNED, TO THE EXTENT PERMITTED BY LAW, HEREBY WAIVE
ANY RIGHT TO HAVE A JURY PARTICIPATE IN RESOLVING ANY DISPUTE, WHETHER SOUNDING
IN CONTRACT, TORT OR OTHERWISE, AMONG BORROWERS, AGENT, THE LENDERS AND THE
UNDERSIGNED, OR ANY THEREOF, ARISING OUT OF, IN CONNECTION WITH, RELATED TO, OR
INCIDENTAL TO THE RELATIONSHIP ESTABLISHED AMONG THEM IN CONNECTION WITH THIS
AMENDMENT OR ANY NOTE OR OTHER INSTRUMENT, DOCUMENT OR AGREEMENT EXECUTED OR
DELIVERED IN CONNECTION HEREWITH OR THE TRANSACTIONS RELATED THERETO. THIS
WAIVER SHALL NOT IN ANY WAY AFFECT, WAIVE, LIMIT, AMEND OR MODIFY THE ABILITY OF
AGENT AND LENDERS TO PURSUE REMEDIES PURSUANT TO ANY CONFESSION OF JUDGMENT OR
COGNOVIT PROVISION CONTAINED IN ANY NOTE OR OTHER INSTRUMENT, DOCUMENT OR
AGREEMENT BETWEEN BORROWERS, AGENT AND THE LENDERS.

      CORE COMPOSITES CINCINNATI, LLC
By: /s/ Herman F. Dick, Jr.
Name: Herman F. Dick, Jr.
Title: Vice President & CFO—  
CORE COMPOSITES CORPORATION
By: /s/ Herman F. Dick, Jr.
Name: Herman F. Dick, Jr.
Title: Vice President & CFO—
   
CORE AUTOMOTIVE TECHNOLOGIES, LLC
By: Core Molding Technologies, Inc.,
Its sole member
By: /s/ Herman F. Dick, Jr.
Name: Herman F. Dick, Jr.
Title: Vice President & CFO—

SCHEDULE 1

COMMITMENTS OF THE LENDERS*

         
LENDERS
  KeyBank National Association
 
       
COMMITMENT PERCENTAGE
    100 %
 
       
REVOLVING CREDIT COMMITMENT AMOUNT
  $ 8,000,000.00  
 
       
TERM LOAN COMMITMENT AMOUNT
  $ 0.00  
 
       
CAPEX COMMITMENT AMOUNT
  $ 8,428,571.00  
 
       
EXPANSION REVOLVING CREDIT COMMITMENT
  $ 10,000,000.00  
AMOUNT
       
 
       
MEXICAN LOAN COMMITMENT AMOUNT
  $ 4,800,000.00  
 
       
IDRB LETTER OF CREDIT COMMITMENT AMOUNT
  $ 1,632,767  
 
       
MAXIMUM AMOUNT
  $ 32,861,338.00  
 
       

         
TOTAL COMMITMENT AMOUNT:
  $ 32,861,338.00  
 
       

*Effective as of the Sixth Amendment Effective Date, taking into account
(a) amortization of principal on the Term Loan Commitment, Capex Commitment and
Mexican Loan Commitment, and (b) reductions in the undrawn amount of the IDRB
Letter of Credit.

EXHIBIT M
FORM OF
EXPANSION REVOLVING CREDIT NOTE

$10,000,000 Columbus, Ohio

June 1, 2011

FOR VALUE RECEIVED, the undersigned, CORE MOLDING TECHNOLOGIES, INC., a Delaware
corporation (“Borrower”), promises to pay, on the last day of the applicable
Commitment Period, as defined in the Credit Agreement (as hereinafter defined),
to the order of KEYBANK NATIONAL ASSOCIATION (“Lender”) at the main office of
KEYBANK NATIONAL ASSOCIATION, as Agent, as hereinafter defined, 88 East Broad
Street, Second Floor, Columbus, Ohio 43215 the principal sum of

TEN MILLION AND 00/100 DOLLARS

or the aggregate unpaid principal amount of all Expansion Revolving Loans, as
defined in the Credit Agreement, as hereinafter defined, made by Lender to
Borrower pursuant to Section 2.4A(a) of the Credit Agreement, whichever is less,
in lawful money of the United States of America.

As used herein, “Credit Agreement” means the Credit Agreement dated as of
December 9, 2008, among Borrower, CoreComposites de Mexico, S. de R.L. DE C.V.,
a sociedad de responsabilidad limitada de capital variable organized under the
laws of Mexico, the Lenders, as defined therein, and KeyBank National
Association, as the lead arranger, sole book runner and administrative agent for
the Lenders (“Agent”), as amended and as the same may from time to time be
further amended, restated or otherwise modified. Each capitalized term used
herein that is defined in the Credit Agreement and not otherwise defined herein
shall have the meaning ascribed to it in the Credit Agreement.

Borrower also promises to pay interest on the unpaid principal amount of each
Expansion Revolving Loan from time to time outstanding, from the date of such
Expansion Revolving Loan until the payment in full thereof, at the rates per
annum that shall be determined in accordance with the provisions of
Section 2.7(j) of the Credit Agreement. Such interest shall be payable on each
date provided for in such Section 2.7(j); provided that interest on any
principal portion that is not paid when due shall be payable on demand.

The portions of the principal sum hereof from time to time representing Base
Rate Loans and Daily LIBOR Loans, interest owing thereon, and payments of
principal and interest of any thereof, shall be shown on the records of Lender
by such method as Lender may generally employ; provided that failure to make any
such entry shall in no way detract from the obligations of Borrower under this
Note.

If this Note shall not be paid at maturity, whether such maturity occurs by
reason of lapse of time or by operation of any provision for acceleration of
maturity contained in the Credit Agreement, the principal hereof and the unpaid
interest thereon shall bear interest, pursuant to the terms of the Credit
Agreement, until paid, at a rate per annum equal to the Default Rate. All
payments of principal of and interest on this Note shall be made in immediately
available funds.

This Note is one of the Expansion Revolving Credit Notes referred to in the
Credit Agreement. Reference is made to the Credit Agreement for a description of
the right of the undersigned to anticipate payments hereof, the right of the
holder hereof to declare this Note due prior to its stated maturity, and other
terms and conditions upon which this Note is issued.

Except as expressly provided in the Credit Agreement, Borrower expressly waives
presentment, demand, protest and notice of any kind. This Note shall be governed
by and construed in accordance with the laws of the State of Ohio, without
regard to conflicts of laws provisions.

The undersigned authorizes any attorney at law at any time or times after the
maturity hereof (whether maturity occurs by lapse of time or by acceleration) to
appear in any state or federal court of record in the United States of America,
to waive the issuance and service of process, to admit the maturity of this Note
and the nonpayment thereof when due, to confess judgment against the undersigned
in favor of the holder of this Note for the amount then appearing due, together
with interest and costs of suit, and thereupon to release all errors and to
waive all rights of appeal and stay of execution. The foregoing warrant of
attorney shall survive any judgment, and if any judgment be vacated for any
reason, the holder hereof nevertheless may thereafter use the foregoing warrant
of attorney to obtain an additional judgment or judgments against the
undersigned. The undersigned agrees that Agent’s attorney may confess judgment
pursuant to the foregoing warrant of attorney. The undersigned further agrees
that the attorney confessing judgment pursuant to the foregoing warrant of
attorney may receive a legal fee or other compensation from Agent or the
Lenders.

 
CORE MOLDING TECHNOLOGIES, INC.
By:
Name:
Title:

 
“WARNING — BY SIGNING THIS PAPER YOU GIVE UP YOUR RIGHT TO NOTICE AND COURT
TRIAL. IF YOU DO NOT PAY ON TIME A COURT JUDGMENT MAY BE TAKEN AGAINST YOU
WITHOUT YOUR PRIOR KNOWLEDGE AND THE POWERS OF A COURT CAN BE USED TO COLLECT
FROM YOU REGARDLESS OF ANY CLAIMS YOU MAY HAVE AGAINST THE CREDITOR WHETHER FOR
RETURNED GOODS, FAULTY GOODS, FAILURE ON HIS PART TO COMPLY WITH THE AGREEMENT,
OR ANY OTHER CAUSE.”