[Old Redneck]

GM use 20W50 only drove over 100,000 miles with no problem. The best thing one can do is change oil every year and no more then 3000 miles. Keeping the oil clean is most important I have found. I use 15W40 for manny years with no problem. I guess each his own. I know some use the cheapest oil they can buy? That scare me.