I have heard such comments about Quaker State over the years but mainly from other oil companies. Also some talk about a higher water content which causes bubbling when hot. This is all Greek to me but its what I heard.
My preference for Quaker State is based on experience. I am driving an 81 Malibu with about 395,000 miles on it. The oil has been changed regularly at about 3000 mile intervals and has always been QS. The only thing I have done to the engine is change the valve stem seals. I rebuilt the carb but that is not relevant.
I see that Pennzoil is also a Quaker State (or vice-versa) product. Do you have any recommendations to brands other than those?
Thanks.
