<Page>
================================================================================
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington D.C. 20549
FORM 8-K
CURRENT REPORT
PURSUANT TO SECTION 13 OR 15(d) OF
THE SECURITIES EXCHANGE ACT OF 1934
Date of Report (Date of earliest event reported): March 25, 2002
COMMISSION FILE NO. 1-14501
PENNZOIL-QUAKER STATE COMPANY
(EXACT NAME OF REGISTRANT AS SPECIFIED IN ITS CHARTER)
DELAWARE 76-0200625
(STATE OR OTHER JURISDICTION OF (I.R.S. EMPLOYER
INCORPORATION OR ORGANIZATION) IDENTIFICATION NO.)
PENNZOIL PLACE, P.O. BOX 2967
HOUSTON, TEXAS 77252-2967
(ADDRESS OF PRINCIPAL EXECUTIVE OFFICES)
Registrant's telephone number, including area code: (713) 546-4000
================================================================================
<Page>
Item 4. Change in the Registrant's Certifying Accountant
As of March 25, 2002, the Board of Directors determined to engage
PricewaterhouseCoopers LLP as the Company's independent public accountants,
replacing Arthur Andersen LLP, which the Company dismissed. This
determination followed the Company's decision to seek proposals from
independent public accountants to audit the financial statements of the
Company.
The audit reports of Arthur Andersen LLP on the consolidated financial
statements of the Company as of and for the fiscal years ended December 31,
2000 and 2001 did not contain any adverse opinion or disclaimer of opinion, nor
were they qualified or modified as to uncertainty, audit scope or accounting
principles.
During the two most recent fiscal years of the Company ended December
31, 2001, there were no disagreements between the Company and Arthur Andersen
LLP on any matter of accounting principles or practices, financial statement
disclosure, or auditing scope or procedure, which disagreements, if not
resolved to Arthur Andersen LLP's satisfaction, would have caused Arthur
Andersen LLP to make reference to the subject matter of the disagreement in
connection with its reports.
None of the reportable events described under Item 304(a)(1)(v) of
Regulation S-K occurred within the two most recent fiscal years of the Company
ended December 31, 2001. During the two most recent fiscal years of the Company
ended December 31, 2001, the Company did not consult with
PricewaterhouseCoopers LLP regarding any of the matters or events set forth in
Item 304(a)(2)(i) and (ii) of Regulation S-K.
Item 7. Financial Statements and Exhibits
c) Exhibits. The following exhibits are filed with this document:
Exhibit No. Description
- ----------- -----------
16 Letter from Arthur Andersen LLP to the Securities and Exchange
Commission dated March 25, 2002
<Page>
SIGNATURE
---------
Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.
PENNZOIL-QUAKER STATE COMPANY
REGISTRANT
/s/ Michael J. Maratea
----------------------
Michael J. Maratea
Vice President and Controller
March 25, 2002
<Page>
EXHIBIT INDEX
Exhibit No. Description
- ----------- -----------
16 Letter from Arthur Andersen LLP to the Securities and Exchange
Commission dated March 25, 2002