Originally Posted By: 2015_PSD
Originally Posted By: racin4ds
This is why I will not run a 20W oil in my fords when towing/working them hard. I know ford recommends it and all the thin oil crowd on here swears by it but if yo use your truck like a truck and monitor oil temps and oil pressure you'll quickly see why you need 30W at a min.
Totally disagree! I have towed in the mountains in temperatures of 117F and I have
UOA'ed every OC and there is zero evidence of the oil breaking down and certainly there was no engine damage. While I will unequivocally state oil is not a one size fits all, I will say the fear mongering that exists with xW-20 is unfounded.
The xW-20 won't break down or anything, but if the engine is being worked hard enough (and especially if it's got some miles and wear on it), it's possible for it to get too thin and not hold adequate pressure to keep everything happy.
If that's happening and the temps aren't high enough to make you say "holy [censored], this needs an oil cooler!", then the problem can be solved by just stepping up a grade oil-wise, as an xW-30 will remain thick enough to keep adequate pressure and keep the engine happy at higher temps than the xW-20 would in the same engine.
Adding an oil cooler also solves the issue by keeping the temps in a range where the xW-20 is adequate for the engine. Keep in mind, OEMs typically design and spec to the 90% of users, not necessarily including the 10% that run their stuff hard and use it to its full ability (excluding dedicated track packs and such). It's usually not too hard to find a cooling limitation or other issue with a stock vehicle being run flat-out in hot weather.