errance

My car is a C6 with Z51. I've been running the factory-recommended Mobil1 5W-30.

How hot is too hot for this oil? When does it start breaking down or no longer does its job? I'm trying to figure out at what threshold I need to start worrying.

Thanks

Z11409

Mobil 1 Hot Temperature Properties

So what value is this at high temperatures? At high temperatures the oil molecule in synthetic oils are far more stable and degenerate less. This means not only do synthetic oils maintain lubrication integrity, they continue to cool and clean engine components at constant temperatures of up to 180°C, and can handle short term temperatures in excess of 200°C.

errance

WHAT?!?!?
My oil is above 200F 100% of the time on the race track!

DarkMastyr

180c = 356f

errance

Doh! I missed the 'C' in Z11409's reply.

That's really ironic because I come from a metric country and F is still new to me.

Thanks DarkMastyr for setting me straight.

So... sound like temps in the low 280s with spikes in the low 290s is nothing to worry about?

AU N EGL

Normally we tell ppl that 250-260* F should be your max sustained running oil temp.

If it gets above that it will not kill your car. But if your constantly seeing temps above that 260*F mark, time to install an oil cooler. EOC in the radiator or stand alone. If your seeing oil temps in excess of 300*F time to short shift and get that oil temp down.

Oil also breaks down at higher temps temps. Look at the SHEER ratings of different oil viscosity.

If your doing track days, consider upping the viscosity of the oil you use. 10-w30 at a min. 40wt racing oil, or 15-w50

Change oil often and send samples to bob the oil guy for analysis.

ccj

errance,

When running at Pacific Raceway or PIR (C5Z06) I was typically seeing 290+F sustained temps for a session (during spring/summer events). When it hit 300F I backed off for few laps. I ran this way for 3 (6-7 events/season) seasons.

I have since added an oil cooler and the temp doesn't get over 275F.

If your worried about the temps give Carlo @ TC Motorsports (Auburn, WA) a call. They might be able to put together an oil cooler for you pretty reasonably.

touring2

You probably arent' here since this is so many years old, and youwent to the dark side in an S4. LOL but This brings back memories, Clark. You were about there on track when I saw you coming after me, I hammered the throttle to get away, and went into the berm at track out of Turn 6!! Fun!
"When running at Pacific Raceway or PIR (C5Z06) I was typically seeing 290+F sustained temps for a session (during spring/summer events). When it hit 300F I backed off for few laps. I ran this way for 3 (6-7 events/season) seasons.

I have since added an oil cooler and the temp doesn't get over 275F.

If your worried about the temps give Carlo @ TC Motorsports (Auburn, WA) a call. They might be able to put together an oil cooler for you pretty reasonably.[/QUOTE]"

seamus2154

If your tracking and getting up to 260 the first thing to do is run 15w/50 for the track. 0w/40 for cooler weather track and street.

Gordy M

With the synthetic oils, it is not the high temps that break down the oil, it is the high temps that break down the additives in the oil.

ccj

"[/QUOTE]

I am still around just inactive. Still have the C5Z and just dropped it off to get Heads, cam and intake installed. Were you in a black C6 Z06 ?

blueray16

So, I have a new LT1 crate engine in my '16 Z51 and need to decide on whether to run M1 0W40 or M1 15W50 at Watkins Glen this year.
Looking back over Cosworth toolbox max oil temps the last 3 years at the Glen, always in June: I find this:
2017 with 15W50 and M1 oil filter max oil temp was 262.
2018 with 15W50 and PF64 filter max oil temp was 284.
2019 with 0W40 and PF 64 filter max oil temp was 264. I set a new personal best by 2 full seconds.
Just on these stats it would seem to me that the 0W40 performed as well or better than the heavier 15W50. Maybe because the 0W40 flows faster? Can't imagine the different oil filters had any effect.

Need help to decide which way to go.

BTW the stock engine dropped a valve (brkn valve spring ) at 62000 miles while cruising on the highway at 55 mph NOT on the racetrack

Black E

was that the new ESP 0w40 or the old euro spec 0w40?

blueray16

That was the new Mobil ESP dexos 2 0W40.

I actually just now recalled that I had added the Corvette secondary radiator prior to the Glen in 2019. That would explain the improvement in oil temps.
With that new bit of info, I'm now more strongly in favor of fresh 0W40 ESP for my track events.

davidfarmer

when the c5z06 first came out...brilliantly without an oil cooler....I was consistently seeing 320F at the track. I don't recommend it, but GM seemed to have no problem with this back then.

Trosscam

Based on what I've been able to find through LS engineers, engine builders and the oil gurus, the goal is to stay above 10ct at the highest sustained operating temp. So if a 5w30 is rated at say 10.5 @ 100c there's no way its staying above 10 if you're running oil temps at 250-300f. So if you're just starting out and not running the car hard and building these higher temps, a good 5w30 is probably fine. Once you start getting up there in the oil temps, ideally you'd move to a more properly matched oil. GM spec'd 15w50 in some applications for track use for this very reason.