I agree completely ^, it seems like most engine failures are a cause of an oil problem. Locking up the bottom end usually means it was an oil problem. Premature failure is usually an oil problem. Oil is key in engine health.

 

Even with the 5W30 that has been in the engine, the oil temp gauge has been between 200-225 even in the 100 degree day with the AC on both high speed ont eh highway and in traffic. Haven't seen it go above 225. Oil cooling seems to be fairly consistent which is good. Now that cooler weather is coming, it should be even better.

 

I was curious about the temperature component. as my car is Canadian, my gauge reads in Celsius. The gauge ranges from 60 - 120 degrees. I noticed that it usually sits at 80 degrees (176 F - 10 to 11 oclock position) on my hour commute, which is a lot of gear changing and some fast reving through country roads. I was surprised that there is no red section on it, and the 12 oclock position is (100 degrees 212 Celsius). So if others are running at 215 degrees normally, I would suggest that a heavier oil could bring that temperature down by 30-40 F, which seems pretty substantial, and worthwhile investigating. In extreme temps like we have, I would go 40W in summer ordinarily.