AverageVetteNut

Ok, so here's what I've been noticing.

1st, let me say that my car is 100% stock as far as drivetrain goes. The car as about 86K miles on it and never been opened up.

When I would go to events and NOT have a co-driver the temps would climb a little but not get too bad but now that I have co-drivers @ most events, I'm noticing higher temps on both the oil temp and the coolant temp. I recently had an oil temp hit 250 for a brief period and mostly on an 80+ degree day, it hovers around 240 during the runs.

I started running the AC on high and open the hood in between runs and that helped a bit ( about 5 minutes between my co-drivers and my runs ), but @ our last local event we were really having our time between runs cut down due to small heat #s.

So, my questions are what can I do to help keep the temps in check for both the oil and engine temps?

I have been running redline oil ( 5W-30 ) in the car and regular 50/50 antifreeze in the car.

Would a different weight oil help? What are the downsides and upsides to that? I admittedly don't know a ton about the weights and what they do, so I'm open to some teaching

Would flushing the coolant help? Can having too MUCH coolant in the system have an adverse affect on it? If I DO flush it, how much does one of these cars need?

I can't change the thermostat to a cooler running one ( to kick the fans on earlier I presume? ) since I'm in stock class SCCA.

Any other tips or tricks ( that are legal ) that I can try I'm all for trying.
SCCA Solo Nationals are two weeks away and it could get very hot there ( as it has in the past ) and I not only want the car running as good as possible but don't want to hurt the car.

Thanks in advance

2 GTOs

I don't think 240 is anything close to worrying territory. My stock Pontiac G8 is always 225 and my C5 hits 280-300 on the road course before I back off based on what I have read in other threads.

As long as it is a synthetic, I think most will say not to worry.

AverageVetteNut

Ok, just got worries that in not so hot days this is happening and wanted to be sure I'm not going to screw things up if it's gets too hot.

Was thinking about keeping some bags of ice handy to put on top of the engine between runs.

froggy47

Replace radiator with new stock one.

Bill Dearborn

Your oil temp isn't outrageous. When I first got my C5Z in 03 I went to a road course and in 85+ ambient air my oil temp hit 319 after a 40 minute run. That is one degree shy of setting off the high oil temp warning. Typically, it would run in the 285 to 290 range until I put an oil cooler on it. Since you don't get going very fast an oil cooler may not help all that much. One thing you can do is make sure all the air coming through the under bumper intake is going through the radiator and not bypassing it. The foam seals between the shroud and the AC condenser tend to blow outward into the engine compartment and let air bypass the radiator. It is easy enough to check all you have to do is open the hood and inspect the area where the shroud meets the AC. To keep things sealed I used duct tape at the top of the shroud.

Bill

AverageVetteNut

Thanks guys. Since this is my 1st Vette and I'm still learning how the car ticks I haven't been sure if I'm just a little paranoid and over cautious about it.

I'll check that out when I work on the car tomorrow.

skyavonee

First thing is to make sure your radiator isn't clogged. clean out the fins with a wire brush and/or blow compressed air through it from back to front.

Second, take Bill's advice above. Here's how I tackled the problem:
corvetteforum.com/c5-z06-discussion/radiator-mod-for-more-efficient-cooling.html
If you're not worried about looks, I'm sure just slapping on some duct tape would also work fine.

Lastly, is computer tuning allowed in the stock class? The radiator fan on/off temps can be reprogrammed without switching to a lower temp tstat. Set your first fan to stay on until it gets down to ~195. I forget exactly what stock settings are, but they're definitely higher than that.

acrace

I never monitored oil temps. In the four years that I ran my '03 Z the highest that I saw coolant temps was in the upper 220s (two drivers, hot days). Admittedly my car has low miles (just broke 10k two weeks ago), so I know that the radiator is clean.

As some folks have posted, check the radiator for debris and that the fins are straight. If you haven't flushed the radiator, I would do it. Actually, I didn't flush it, just changed the coolant after 4-1/2 years. Still looked really good. I didn't do anything "trick", just used Dexcool. Forgot the amount it takes.

I turn on the A/C as soon as I'm headed back to my grid spot. Hood up, car keeps running, and sometimes I spray down the radiator.

Have fun at Nationals. Not going this year. Hopefully it won't be as hot as last year (although SS didn't run in the heat of the day last year). I thought I saw that SS runs first heat?


Al Chan
2003 Z06
2009 Z06

Supercharged111

Low speed fan won't even kick on until like 225, I just reflashed my car to drop the fan temps clsoer to 200. Refoaming the AC is only part of it, if you look there's a nice fat gap between the center lip and the bottom of the radiator/AC. After cutting holes in the stock radiator fan shroud, I'll be sealing up that gap for yet another low buck cooling mod. The other 2 being 33ish percent coolant with water wetter and taping off the stock Z06 screens to maximize the pressure differential across the radiator when at the track. I know as I get faster and start beating the car harder, I'll eventually need to drop coin on a bigger radiator, but for now I'm trying to maximize what I have.

AverageVetteNut

Sorry to hear you're not making it. I was looking for your name on the list. I most likely won't be there next year.

Yes, that's one nice thing as far as heat is concerned, that we're running 1st heat, but working 5th could suck...lol

I have no idea if/when the coolant has been swapped out, so Maybe I'll just go and replace the fluid and check the radiator fins and such.

Looks like I've got a nice project for today.