I thought I read somewhere on here that most cars designed for Dino oil don't exceed 204oF and Synthetic is for temperatures higher than that up to like 300oF or something...
Don't quote me... Can someone confirm?
I know that in diesel trucks I work on at work, the oil temperature generally stays even with the coolant temp, as long as your not working the engine real hard. Most of them are using dino oil in them, and its not uncommon to see oil and coolant temps hit 215*F. Ofcourse, they have oil coolers, so you would expect the oil and coolant temps to be pretty close under light duty driving. I'm not sure though what its like on a passanger car without an oil cooler. I know my Jeep's coolant easily hits 215-220*F in the summertime and it has no oil cooler. Unfortunately, I don't have an oil temp. gauge for it, so I don't know if oil temp stays relatively close to coolant in that type of application.
On track, people max at 230* with a 25-row Mocal cooler. Not sure where it'd be with the factory oil-water cooler. Engine is out right now, and didn't have a temp gauge before. I'd guess it max is 260-270* with the oem cooler.
For practical purposes though, if Penzoil or Mobil1 tell me their 10w30 won't break down at these temps (260-270) I have nothing to worried about as wear as wear goes right? Aftermarket oil coolers aren't cheap.
Whats the upper temp of oil passing through a oil cooled Turbo?
I would think that a quality synthetic could handle 250F easy.
I know turbo's get pretty darn hot, since the oil flowing through them is moving it dosent get THAT hot, but still.
I was seeing 290 temps in the GN when it had severe blowby problems and this was on dino oil and light to moderate driving. I drove the car accordingly, giving it time to rest so it never sustained 290 for more than about 20 minutes but I can say dino can take it for short amounts of time. If it was not going to get a rebuild anyway I would've definately run synthetic in it.
I normally see 210*F (LT1 with no oil cooler) after extended driving. It will creep towards 250*F when Im romping down the highway (70mph zone) at speeds slightly more than the limit. Taken from oil filter adapter. 160* T-stat, 3.73s, 4l60e, and 26" tall tires.
I've seen 285 on the roadcourse in my turbocharged 2.4l 4cyl. I normally use Redline 10w40 at the track, ASL for daily driving. Daily driving cruising temps are 195, same as the t-stat since I have a coolant/oil heat exchanger.
Here is a UOA that had 2 track days, 90+ degrees each day, 275-285 oil temps for 30 minutes at a time, 4 times a day. Total track miles were right around 350 miles. The rest of the miles were daily driving. high lead was from the race fuel used at the track.
EDIT: 2750 mile run is GC 0w30, and the Lucas they mention was fuel additive, not oil additive. I think they thought I added the oil stablizer when I mentioned the lucas additive to them