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High coolant temps?

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Old Aug 18, 2006 | 06:30 PM
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Default High coolant temps?

I have been driving my '99 FRC for the last couple of days because the daily driver is in the shop. It has been about 106* during the heat of the day here in Dallas. When I am in stop and go traffic my temp has gotten as high as 135*. The temp will drop back down to aroung 210* when I get back moving in clean air. I have the hypertech 180* t-stat and the fans have been reprogrammed with the hypertech reprogrammer. I know the cooler the operating temp the better, but is it damaging for it to get this hot for short periods of time? I put the windows down and turned on the heater until I got out of traffic because I didn't want it to get any hotter. With the heater on it cooled it back down to around 225*. Any input from you pros out there would be great. Thanks, Sean
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Old Aug 18, 2006 | 06:41 PM
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Originally Posted by Redline!
I have been driving my '99 FRC for the last couple of days because the daily driver is in the shop. It has been about 106* during the heat of the day here in Dallas. When I am in stop and go traffic my temp has gotten as high as 135*. The temp will drop back down to aroung 210* when I get back moving in clean air. I have the hypertech 180* t-stat and the fans have been reprogrammed with the hypertech reprogrammer. I know the cooler the operating temp the better, but is it damaging for it to get this hot for short periods of time? I put the windows down and turned on the heater until I got out of traffic because I didn't want it to get any hotter. With the heater on it cooled it back down to around 225*. Any input from you pros out there would be great. Thanks, Sean
Get the fins on your radiator blown out from the engine compartment side, top (especially) to the bottom. Had a friend go through the same thing when we were at the Black Hills Corvette Classic. The dealer changed thermostats, flushed the engine, etc., and no change. He took it back and had them clean the radiator fins, and presto!, his problem went away. Of course, the dealer also padded his pocket on the deal with the unneeded thermostat change and coolant flush.
Ed

Last edited by C5XTASY; Aug 19, 2006 at 07:44 AM.
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Old Aug 18, 2006 | 10:17 PM
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Thanks for the info. I will give it a shot.
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Old Aug 19, 2006 | 09:02 AM
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Originally Posted by Redline!
I know the cooler the operating temp the better, but is it damaging for it to get this hot for short periods of time?
Cooler operating is not necessarily better, your car was originally designed to run hotter than the engines of the past, from the factory your first cooling fan is programmed to come on at 225 degrees.

On another note, since the C5 is a bottom breather look under your car at the front of the radiator to make sure there are no obstructions and if it's clear you can remove your air bridge and upper radiator support to get better access to the radiator to blow debris out (you'd be surprised how much dirt and sand get stuck in the fins) also with the upper radiator support removed you can clean out any debris between the radiator and the a/c condensor.
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Old Aug 19, 2006 | 09:19 AM
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Originally Posted by Redline!
I have been driving my '99 FRC for the last couple of days because the daily driver is in the shop. It has been about 106* during the heat of the day here in Dallas. When I am in stop and go traffic my temp has gotten as high as 135*. The temp will drop back down to aroung 210* when I get back moving in clean air. I have the hypertech 180* t-stat and the fans have been reprogrammed with the hypertech reprogrammer. I know the cooler the operating temp the better, but is it damaging for it to get this hot for short periods of time? I put the windows down and turned on the heater until I got out of traffic because I didn't want it to get any hotter. With the heater on it cooled it back down to around 225*. Any input from you pros out there would be great. Thanks, Sean
135 seems awfully low when the outside air temp is 106. I would check that out.
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Old Aug 19, 2006 | 10:02 AM
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Originally Posted by EHS
135 seems awfully low when the outside air temp is 106. I would check that out.
I think that was a typo...if you read on a bit... I thought the same thing..I was like damn.....tell me your secret
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Old Aug 19, 2006 | 12:50 PM
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Originally Posted by pewter99
I think that was a typo...if you read on a bit... I thought the same thing..I was like damn.....tell me your secret
Oh, yes, I see now.
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Old Aug 25, 2006 | 02:22 PM
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Just got a chance to check this thread and see your advice. Thank you. I am going to work on it this weekend. Yesterday it got as high as 240. It always cools right back down when I get in clean air. I bet the radiator is just dirty. I have checked the fans and they are working good. I will clean the outside and if that does not work I will get the radiator flushed. Thanks again for all of your input.
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Old Aug 25, 2006 | 05:19 PM
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Sean, As a side note: When you are in stop and go traffic in heat you can turn on your a/c. This overrides your cut in set point for both fans and with them on it will cool some. Once you are out of stop and go you don't get as much effect, as you now have some air flow thru the rad at speed.
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Old Aug 25, 2006 | 06:11 PM
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...once you check you radiator area for debris that might be blocking air flow, buy (or build yourself) a screen to block junk from getting up between the shroud and radiator core (plastic bags, squirrels, birds, etc).
ELITE ENGINEERING is a site vendor and sells a very nice manufactured screen which is a bolt in.
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Old Aug 25, 2006 | 10:45 PM
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Sounds like great advice. Thank you.
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Old Aug 26, 2006 | 01:44 PM
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You may also want to try a product called "water wetter". Pour it in your radiator. Some people have reported temps dropping by 10 degrees.
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