My local WalMart told me along time ago that their house oil is produced by Quaker State. I use their 10-40 Blend in my F250 with 160,000 miles and it works as good as Valvoline did, in fact the Blend is for high mileage engines just like MaxLife, and they even have a full synthetic for high mileage engines which I plan to use next since the blend hasn't caused any further leaks or useage. I agree for the most part with JHZR2. I have been driving for almost 40 years with a state drivers lic. and a few more before that and I have never lost an engine because of oil, as long as the engine had it's fill, and I wrenched about 30 years. I can say that I saw an engine in the 70s that the owner claimed to have run Pennsoil and when I pulled the pan the inside had what looked like thin cardboard pieces stuck to the pan and block and there was no doubt it was from the oil.