Personally in the 70's and 80's I had several situations where customers using Pennzoil following recommended OCI were having significant sludge and varnish in the top end. Word of mouth at other auto repair shops, was many saying to avoid Pennzoil due to it being paraffin based causing sludge problems. Ever since then, I've always advised against using Pennzoil and even have avoided such in company cars.
Years later, after going through college and working with a major energy & lube company, I came to learn that Pennzoil had issues for several years with their dewaxing processes during base oil refining, which resulted in less than perfect lubes. There is nothing inherently wrong with parafin base stocks versus napathentic, but that point can regress into another debate.
Anybody else have similar experiences with Pennzoil during this era?
Years later, after going through college and working with a major energy & lube company, I came to learn that Pennzoil had issues for several years with their dewaxing processes during base oil refining, which resulted in less than perfect lubes. There is nothing inherently wrong with parafin base stocks versus napathentic, but that point can regress into another debate.
Anybody else have similar experiences with Pennzoil during this era?