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                                                                  EXHIBIT 99.15

                 FIRST AMENDMENT TO 1994 EMPLOYEE NON-QUALIFIED
              STOCK OPTION AGREEMENT OF MOTORVAC TECHNOLOGIES, INC.



        THIS FIRST AMENDMENT TO 1994 EMPLOYEE NON-QUALIFIED STOCK OPTION
AGREEMENT OF MOTORVAC TECHNOLOGIES, INC. (the "Amendment") is made by and
between Motorvac Technologies, Inc., a Delaware corporation (the "Company"), and
_________________, an employee of the Company (the "Optionee"), effective as of
August 15, 1996.

        WHEREAS the Company and Optionee have previously entered into an
Employee Non-Qualified Stock Option Agreement (the "Stock Option Agreement");

        WHEREAS, the Board of Directors of the Company has adopted amendments to
the Motorvac Technologies, Inc. 1994 Stock Incentive Award Plan (the "Plan") to
provide for the immediate exercisability of all outstanding options under the
Plan upon the occurrence of a Terminating Transaction (as defined in the Plan);
and

        WHEREAS, the Company and Optionee desire to enter into this Amendment in
order to amend the Stock Option Agreement to provide that all outstanding
options evidenced by the Stock Option Agreement shall become immediately
exercisable upon the occurrence of a Terminating Transaction.

        NOW, THEREFORE, in consideration of the mutual covenants herein
contained and other good and valuable consideration, receipt and sufficiency of
which is hereby acknowledged, the parties hereto do hereby agree as follows:

1.      AMENDMENT.

        (a) Section 3.3(f) of the Stock Option Agreement is hereby amended and
restated in its entirety to read as follows:

               "(f) The expiration of ten (10) days from the effective date of a
Terminating Transaction, unless in connection with such Terminating Transaction,
the Optionee suffers a Termination of Employment, in which case the provisions
of Sections 3.3(d)-(e) hereof, as applicable, shall be controlling with respect
to the expiration of the Option. At least ten (10) days prior to the effective
date of any Terminating Transaction, the Committee shall give the Optionee
notice of such event if the Option has then neither been fully exercised nor
become unexercisable under this Section 3.3."

        (b) Section 3.4 of the Stock Option Agreement is hereby amended and
restated to read in its entirety as follows:


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        "SECTION 3.4 - ACCELERATION OF EXERCISABILITY. Upon the occurrence of a
Terminating Transaction and for a period of ten (10) days thereafter, this
Option shall be exercisable as to all of the shares covered hereby,
notwithstanding that this Option shall not yet have become fully exercisable
under Section 3.1(a); PROVIDED, HOWEVER, that this acceleration of
exercisability shall not take place if:

               (a) This Option becomes unexercisable under Section 3.3 prior to
the effective date of the Terminating Transaction; or

               (b) In connection with such Terminating Transaction, provision is
made for an assumption of this Option or a substitution therefor of a new option
by a successor corporation or a Parent Corporation or Subsidiary Corporation of
such corporation.

The Committee may make such determinations and adopt such rules and conditions
as it, in its absolute discretion, deems appropriate in connection with such
acceleration of exercisability, including, but not limited to, provisions to
ensure that any such acceleration and resulting exercise shall be conditioned
upon the consummation of the contemplated Terminating Transaction and
determinations regarding whether provisions for assumption or substitution have
been made in accordance with subsection (b) above."

2. MISCELLANEOUS. Except as amended hereby, the Stock Option Agreement remains
in full force and effect. This Amendment shall be governed by and construed in
accordance with the laws of the State of California and may be amended only by a
written instrument executed by each of the parties hereto. In the event of any
inconsistency between the Stock Option Agreement and this Amendment, this
Amendment shall control.

        IN WITNESS WHEREOF, this Amendment has been executed and delivered by
the parties hereto as of the date first above written.

                                            MOTORVAC TECHNOLOGIES, INC.,
                                            A DELAWARE CORPORATION


                                            BY:
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                                                ALLAN T. MAGUIRE
                                                VICE PRESIDENT OF FINANCE

                                            OPTIONEE

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                                            PRINT NAME:
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