JeremyGSU

Hey guys I just got back from Sebring and I was wondering what coolant temps you guys are seeing. I have an '04 C5 Z06.

I have the stock radiator and Ron Davis oil cooler. With a mix of 80 water / 20 coolant and water wetter I saw as high as 244 F water. This was brief staying mostly in the 230's on track consistenly. Another guy with a Z like mine said he was typically hitting 240 as well.

I've seen almost 230 on the street so I can't see why this is an issue but I am curious as to what others are hitting consistently before considering a larger radiator.


Jeremy

travisnd

That's not normal when on track and moving. Especially this time of year. 230s on the street is only normal when stationary. My car stays under 220 even in the hottest months, but I have no AC in the way and I run distilled water with water wetter. I usually keep oil temp up on the DIC and rarely watch coolant. I doubt I was getting over 200 this past weekend at VIR.

Bill Dearborn

I usually paid more attention to my oil temps on the DIC than the coolant temp. If your coolant temp is getting to 244 with lots of air blowing through the radiator your oil temp must be getting high as well. When I first got my 03Z I was doing 40 minute sessions in August and was hitting ~230 coolant and 319 oil temps. Around town coolant temps can get into the 240s depending on how hard you are pushing the engine, how hot the ambient air is and whether or not you have the AC on.

I did put in a Ron Davis Racing Radiator/EOC and with a stock coolant thermostat and no oil thermostat the coolant temp stayed at 200 and oil temp at 230.

Bill

geerookie

I have a Dewitts 2 core Direct Fit I just pulled out of the race car if you are interested. I never saw temps above 215 with it and that was on a 105 degree day at VIR.

$400 plus shipping.

VetteDrmr

You didn't mention your oil temps, but those coolant temps are pretty darned high. Check your airflow: air dams in place, clean out debris out of the oil cooler, condensor, etc.

After that check that your coolant is full and you leave enough room in the expansion tank.

HTH, and have a good one,
Mike

thatonedude1

Agree with others that those water temps are a bit too high, but I think your pressing concern should be oil temp. If oil tem was at 250 degF and water at 240 degF, I would not worry too much, but if oil is nearing 300 degF, then I would definately worry and be thinking about running a 40 weight oil on the track and upgrading the oil cooler to get temps down. I think about 220 degF water and 240 ish degF oil would be great at the track.

travisnd

You're never going to see 240 oil temp racing in hot weather. I have the DRM stand-alone cooler kit with the larger Setrab 625 cooler and the car gets in the high 250s when racing in the summer heat. That's about as good as you're going to do on a C5.

ZedO6

straight water and Water Wetter is the first change I'd make. Coolant will not help keep the water temps down. I just get used to changing coolant a few times a year, which is necessary if you are not running coolant.

JeremyGSU

Sorry I didn't mention oil temps. At Road Atlanta in Nov. I was hitting 300 oil. I bought a Ron Davis 625 oil cooler and was hitting 255 oil temps last weekend. This was in 91-92 degree weather. Sebring gets humid and is usually hot year round. I am still running some coolant because it is still a street car and I drive it to-from track. Driving home oil was as low as 140s-150s when cruising on the highway at 80. Coolant was 172.

JeremyGSU

I also recently installed a 160 degree thermostat too. It took a number of HARD laps to reach the 230s. Some sessions I was inly seeing high 220s. The highest I saw was 244. That was in the afternoon after around 4-5 hard laps.

Falcon

Necessary to change coolant if not running coolant...I don't understand?

Falcon

On hot days, the coolant in the LS6's runs in the 230's. Just blow the radiator out as part of the prepping process and get used to those temps.

The oil temp usually runs 250'ish with a stand alone oil cooler. That temp is influenced more by high RPM's than anything else.

ZedO6

What I meant was I change out the water/Water Wetter mix so that the dissimilar metal cocktail that is created with an iron water pump impeller/shaft in an aluminum block won't get strong enough to start eating stuff. Out here in CA, I never have run coolant in my track cars.

stevensa

I have an 02 Z06 with the DRM Ron Davis Radiator/built in oil cooler. The hottest day I have ever ran in was 109F ambient in August in Houston at Texas World Speedway. My oil temp was 255F and Coolant was 196F. On an average day my coolant is ~192F and oil ~245F.

waddisme

I have the DeWitts with 160* tstat. Even in the hot of summer I never see water temps above 200*. I knocked one of my air dams off at VIR last year and temps went to almost 210*, but not even close to that since repl. I could hit 300*+ with oil easily until I installed the Setrab 625 cooler. Highest I have seen since is 254* at VIR in September.

longdaddy

is your oil cooler right next to the radiator? they may be exchanging heat which is fine as long as your coolant does not boil. as others said, oil temp is the important indicator.

i'd clean out the radiator as a first measure - it would help both oil and coolant temps. blow it out in reverse to normal airflow with compressed air or pressure washer. You may need to take it out, or to take the fans out to get good access.