Where is the proof of this though? There are quite a few examples of good old American and Japanese engines going hundreds of thousands of miles, running 5w30 and 10w30 also. I don't hear many stories of European cars going 500,000 miles, other than Volvos.quote:
Originally posted by Dr. T:
I believe the UOA's don't give the whole story. Traditionally, thicker oils have been used and are recommended when 1. racing (high temp/high punishment conditions) 2. long drain intervals (I can't see too many engines going 10k mi. intervals on convenience-store 5-30) 3. engine life is a priority (Euro. engines last longer than U.S.).
Terry Dyson has viewed literally thousands of UOAs over the years, and he knows I want maximum engine life out of my LT1. You know what he recommends to me? 10w30. I'm sure if he saw any evidence that 50wt oils make our engines last longer, he would've told me to use this thick oil in the summer. The fact that he didn't, speaks volumes, IMHO.