The addition of Torco ZEP to any modern motor oil will put back the proper amount of Zinc Dialkyl-Dithiophosphate (ZDDP) purposely taken out to be catalytic converter friendly. ZEP coats all engine parts and won’t rub, scrape or scrub off and protects engines that are occasionally used from “dry starts”, a leading cause of premature engine wear of vehicles kept in storage.
