SECOND AMENDMENT


     THIS SECOND AMENDMENT dated as of July 27, 2001 (the "Amendment") amends
the Credit Agreement dated as of August 2, 1000 (the "Credit Agreement") among
A.O. SMITH CORPORATION (the "Company"), various financial institutions (the
"Lenders"), BANK ONE, NA (formerly known as The First National Bank of Chicago),
as Syndication Agent, and BANK OF AMERICA, N.A., as Agent. Terms defined in the
Credit Agreement are, unless otherwise defined herein or the context otherwise
requires, used herein as defined therein.

     WHEREAS, the Company, the Lenders, the Syndication Agent, the Agent have
entered into the Credit Agreement; and

     WHEREAS, the parties hereto desire to amend the Credit Agreement as more
fully set forth herein;

     NOW, THEREFORE, the parties hereto agree as follows:

     SECTION 1 Amendments. Effective on (and subject to the occurrence of) the
Amendment Effective Date (as defined below), the Credit Agreement shall be
amended as set forth below:

     1.1. Definition of 364-Day Credit Agreement. The definition of "364-Day
Credit Agreement" in Section 1.1 is amended in its entirety to read as follows:

               364-Day Credit Agreement means the Amended and Restated Credit
          Agreement dated as of July 24, 2001 among the Company, various
          financial institutions and BofA, as Agent.

     1.2. Amendment to Subsection 2.11(c). Subsection 2.11(c) is amended in its
entirety to read as follows:

               (c) Utilization Fees. The Company shall pay to the Agent for the
          account of each Lender a utilization fee on such Lender's Pro Rata
          Share of the aggregate principal amount of all outstanding Committed
          Loans for any day on which such aggregate principal amount exceeds 50%
          of the Aggregate Commitment Amount, computed at a rate per annum equal
          to 0.05% or, at any time the Leverage Ratio is greater than 0.55 to 1,
          0.075%. Such utilization fee shall accrue on each applicable day from
          the Closing Date to the Termination Date and shall be due and payable
          quarterly in arrears on the last Business Day of each calendar quarter
          through the Termination Date, with the final payment to be made on the
          Termination Date.

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     1.3. Amendment to Section 2.17. The first sentence of Section 2.17 is
amended in its entirety to read as follows:

               2.17 Optional Increase in Commitments. The Company may at any
          time (but not more than once in any calendar year), by means of a
          letter to the Agent substantially in the form of Exhibit J, request
          that the Aggregate Commitment Amount be increased by (a) increasing
          the amount of the Commitment of one or more Lenders which have agreed
          to such increase and/or (b) adding an Eligible Assignee as a party
          hereto with a Commitment in an amount agreed to by such Eligible
          Assignee; provided that (i) no Eligible Assignee shall be added as a
          party hereto unless such Eligible Assignee shall have been approved in
          writing by the Agent (which approval shall not be unreasonably
          withheld), (ii) in no event shall the Aggregate Commitment Amount
          exceed $285,714,285.71 without the written consent of all Lenders,
          (iii) at the time of such increase, and after giving effect thereto,
          no Event of Default or Unmatured Event of Default shall exist and (iv)
          both before and after giving effect to such increase, the Company
          shall be in pro forma compliance with all financial covenants set
          forth in Section 7.

     1.4. Amendment to Section 3.7. Section 3.7 is amended by (i) deleting the
language ", or a Lender declines or fails to respond to an Extension Request (as
defined in the 364-Day Credit Agreement pursuant to subsection 2.18(a) of the
364-Day Credit Agreement)" and (ii) deleting the language "or declining or
failing to respond to an Extension Request,".

     1.5. Amendment to Subsection 10.8(a). Subsection 10.8(a) is amended in its
entirety to read as follows:

               10.8 Assignments, Participations, etc. (a) Any Lender may, with
          the written consent of the Company (at all times other than during the
          existence of an Event of Default or Unmatured Event of Default) and
          the Agent, which consents shall not be unreasonably withheld, at any
          time assign and delegate to one or more Eligible Assignees (provided
          that no written consent of the Company or the Agent shall be required
          in connection with any assignment and delegation by a Lender to an
          Eligible Assignee that is an Affiliate of such Lender) (each an
          "Assignee") all, or any ratable part of all, of the Committed Loans,
          the Commitment and the other rights and obligations of such Lender
          hereunder; provided that (i) except in the case of an assignment by a
          Lender of all of its remaining rights and obligations hereunder, the
          amount of the Commitment so assigned shall not be less than
          $5,000,000; and (ii) the Company and the Agent may continue to deal
          solely and directly with such Lender in connection with the interest
          so assigned to an Assignee until (x) written notice of such
          assignment, together with payment instructions, addresses and related
          information with respect to the Assignee, shall have been given to the
          Company and the Agent by such Lender and the Assignee; (y) such Lender
          and its Assignee shall have delivered to the Company and

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          the Agent an Assignment and Acceptance in the form of Exhibit G
          ("Assignment and Acceptance") and (z) the assignor Lender or Assignee
          has paid to the Agent a processing fee in the amount of $3,500.

     1.6. Amendment to Exhibit J. Exhibit J is amended by (i) deleting at the
end of clause (b) the brackets around the word "and", (ii) deleting at the end
of clause (c) the language "; [and" and replacing such language with a period
and (iii) deleting clause (d) in its entirety.

     SECTION 2 Representations and Warranties. The Company represents and
warrants to the Lenders that (a) each representation and warranty set forth in
Section 5 of the Credit Agreement is true and correct as of the date of the
execution and delivery of this Amendment by the Company, with the same effect as
if made on such date (except to the extent such representations and warranties
expressly refer to an earlier date, in which case they were true and correct as
of such earlier date), and (b) the Credit Agreement, as amended hereby (as so
amended, the "Amended Credit Agreement"), is the legal, valid and binding
obligation of the Company enforceable against the Company in accordance with its
terms, except as enforceability may be limited by bankruptcy, insolvency or
similar laws of general application affecting the enforcement of creditors'
rights or by general principles of equity limiting the availability of equitable
remedies.

     SECTION 3 Effectiveness. The amendments set forth in Section 1 above shall
become effective on the date (the "Amendment Effective Date") when the Agent
shall have received counterparts of this Amendment executed by the Company and
the Required Lenders.

     SECTION 4 Miscellaneous.

     4.1. Continuing Effectiveness, etc. As herein amended, the Credit Agreement
shall remain in full force and effect and is hereby ratified and confirmed in
all respects. After the Amendment Effective Date, all references in the Credit
Agreement and the Notes to "Credit Agreement", "Agreement" or similar terms
shall refer to the Amended Credit Agreement.

     4.2. Counterparts. This Amendment may be executed in any number of
counterparts and by the different parties on separate counterparts, and each
such counterpart shall be deemed to be an original but all such counterparts
shall together constitute one and the same Amendment.

     4.3. Governing Law. This Amendment shall be a contract made under and
governed by the laws of the State of Illinois applicable to contracts made and
to be fully performed within such State.

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     4.4. Successors and Assigns. This Amendment shall be binding upon the
Company, the Lenders and the Agent and their respective successors and assigns,
and shall inure to the benefit of the Company, the Lenders and the Agent and the
respective successors and assigns of the Lenders and the Agent.

     IN WITNESS WHEREOF, the parties hereto have executed and delivered this
Amendment as of the day and year first above written.

                                      A.O. SMITH CORPORATION


                                      By: /s/
                                          -------------------------------------
                                      Title:  Assistant Treasurer



                                      BANK OF AMERICA, N.A.,
                                      as Agent and as a Lender


                                      By: /s/
                                          -------------------------------------
                                      Title:
                                            -----------------------------------



                                      BANK ONE, NA (Main Office Chicago), as
                                      Syndication Agent and as a Lender


                                      By: /s/
                                          -------------------------------------
                                      Title:
                                            -----------------------------------



                                      THE BANK OF NEW YORK


                                      By: /s/
                                          -------------------------------------
                                      Title:
                                            -----------------------------------



                                      CITIBANK, N.A.


                                      By: /s/
                                          -------------------------------------
                                      Title:
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                                      FIRSTAR BANK, N.A.


                                      By: /s/
                                          -------------------------------------
                                      Title:
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                                      MARSHALL & ILSLEY BANK


                                      By: /s/
                                          -------------------------------------
                                      Title:
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                                      By: /s/
                                          -------------------------------------
                                      Title:
                                            -----------------------------------



                                      WELLS FARGO BANK, N.A.


                                      By: /s/
                                          -------------------------------------
                                      Title:
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                                      U.S. BANK NATIONAL ASSOCIATION


                                      By: /s/
                                          -------------------------------------
                                      Title:
                                            -----------------------------------



                                      WACHOVIA BANK, N.A.


                                      By: /s/
                                          -------------------------------------
                                      Title:
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                                      GENERAL ELECTRIC CAPITAL CORPORATION


                                      By: /s/
                                          -------------------------------------
                                      Title:
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