Engine Overheating

[Z288racer]

Just finished the break in period (1500 miles) on my brand new Z28 and took it for one day at the Streets of Willow outside Los Angeles. Temperature started around 80 and the high after lunch was 109 - really hot.

In all my runs, even when outside temperature was still 90, after around 15 minutes I got a message that the A/C is OFF due to heat (I had it off to begin with..). Few minutes later the alarm chime went off and the message was - engine overheat, idle the engine - Which I did or just went for cooling laps at very low rpm. Engine water temperature dropped quickly from a high of around 250 to 230 or below and performance driving could resume... High oil temperature was around 290.

Any suggestions? Any similar Experiences?

PS1 The car handles amazingly well and the brakes are fabulous. I took it on the skidpad and it's neutral - perfectly balanced.
PS2 I removed the water deflector below the hood scoop but I did not change the coolant / water mix.
PS3 The water temperature gage in the dashboard seemed useless, and barely moved despite increasing water temperature.

[Doubleblank]

It is strange that some owners experience this and others run hard (like myself) in hot weather and have no issues at all. I've never seen my oil temp above 250 deg, even when running in 100 deg weather. I run the recommended 15-50 oil when on track.

[hammdo]

Set your anti freeze to your environment. Here in DFW, our lowest temp has been - 8 (in 1899) so I set the freezing temp to - 5*. I added 65% distilled water and 35% concentrated anti freeze (not the 50/50) and then added water wetter. That should help you Temps...

Outside of that, dedicated oil cooler and bigger radiator...

-Don

[Stephen12ZL1]

the z/28 already has a dedicated oil cooler but you could add another one. A larger radiator and possibly a check of the thermostat to ensure it is working properly. Adjusting the mix to more like the track prep sheet rx of 70/30 water/dexcool should help a little.

[hammdo]

Yep, 70/30 and maybe a 160* thermostat too...

-Don

[Stephen12ZL1]

Originally Posted by hammdo

Yep, 70/30 and maybe a 160* thermostat too...

-Don

factory thermostat is a 160°F which is suprising

[Stephen12ZL1]

http://www.camaro5.com/forums/showthread.php?t=409726

[hammdo]

Wow, didn't expect that. Thanks I didn't know that one!

-Don

[hammdo]

Does anyone run 100% distilled water and water wetter in their Z/28? I would imagine a flush every year would be required to keep the system fresh...

-Don

[Quasimofo]

Why is there even any debate or questioning of running a cooler thermostat in this car? I'm not really aware of any problems related to a cooler running car, but the problems with a car running hot are well documented. I say that after seeing the info about it having a 160F thermo. and wondering whatever is the issue?!

I understand if the thing runs cool enough to never leave the a warmup cycle in the ecu, but that doesn't seem to be an issue on a car with a large displacement V8 crammed into a relatively small engine bay. At least not in my experience.

[Paul2x]

Streets is a hot track though bc you don't get alot of highspeed air in the car.

I ran Autoclub this past weekend, wasn't over 100 like the desert but had zero issues and was pushing it as temps were my #1 concern, so i purposely stayed out, lap after lap.

I'd just recommend as most of us socal track rats do is avoid the desert tracks for the next few months. We can all meet at big willow in Nov!

Thx for sharing.

[chimazo]

Are any of the cars experiencing the high temps NON-a/c cars? Could the condenser be reducing airflow enough to cause the issue (not that you'd remove your a/c)?

[TJR172]

My water temp never gets too high, but my oil temps get up to 290-300, almost every track day. Thats too high. I run Motul 15-50 racing oil. That stuff is designed for those high temps. Im definitely putting on some additional oil coolers soon. I have AC and will be removing it soon to see if there is a difference.

[X25]

Originally Posted by Doubleblank

It is strange that some owners experience this and others run hard (like myself) in hot weather and have no issues at all. I've never seen my oil temp above 250 deg, even when running in 100 deg weather. I run the recommended 15-50 oil when on track.

Well, then I would have to say I've never owned a car that could stay at 250 degrees F or less at the track ('04 STi, '05 STi, '06 C6 Z51, '06 C6 Z06, '11 EvoX, '12 C6 GS, '13 C6 Z06, '13 Supercharged MX5, '14 1LE). The one that fared best was the '12 Corvette Grand Sport, which stayed around 265-270 degrees F range. I believe Camaros have a very limited air flow compared to what Corvettes have. I am actually surprised they did not use ZL1 frontend on the Z/28 for better flow.

I think it has to do with the local track venues (the ratio of straights vs. streets), the driving style (do you always get to redline?), usual ambient temps, etc. The RPM range used seems to make the biggest impact. What is your average RPMs? (Most track programs provide this data if you collect RPM data through OBD II).

Long story short, my 1LE did not overheat, but I had to let it cool down after every few laps since it came to 290+ degrees F oil in just a few laps, and would get back to that range with just two more laps after a full cool-down lap (of 2+ miles track), and this was with a moderately sized external oil cooler. Keep in mind, LS7 gets to even higher temps due to higher power and RPM range.

I ended up replacing my oil cooler core with the biggest one Setrab sells, and this time my oil temps stabilized in 270s despite my best efforts to overheat. My coolant temps were also around 220 degrees during my 45 minute sessions.

Oil cooler how-to thread: http://www.camaro5.com/forums/showthread.php?t=381050