C5 overheating only when ac is on
Thread Starter
4th Gear
Joined: Apr 2020
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C5 overheating only when ac is on
I have a 98 c5 and for some reason only when the ac is on it tends to overheat while driving only about 10 minutes. As soon as I turn it off the temp goes back to normal. The fans do turn on. What can it be?
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Welcome to the forum and congratulations on your C5!
You may want to post this question in the C5 sections at https://www.corvetteforum.com/forums...s-1997-2004-2/.
Lots of great members and helpful information there.
A few things (although there are many better thoughts from other members):
Double check fans are both spinning about the same rpm;
I imagine you have checked the water level in the radiator and coolant overflow (?)
With your C5 up on a lift, check for junk around the radiator;
Double check you have the center air dam since the C5s are "bottom feeders";
Go to Pep Boys (or similar) and see if they can do a pressure test of your radiator (especially focusing on the radiator cap);
Air in the radiator system?
Also, when you say "overheat" what temps are you seeing?
Any recent mods to the engine?
Again, I'm sure you will get more great info in the C5 section.
Best wishes for an easy (inexpensive) fix!
You may want to post this question in the C5 sections at https://www.corvetteforum.com/forums...s-1997-2004-2/.
Lots of great members and helpful information there.
A few things (although there are many better thoughts from other members):
Double check fans are both spinning about the same rpm;
I imagine you have checked the water level in the radiator and coolant overflow (?)
With your C5 up on a lift, check for junk around the radiator;
Double check you have the center air dam since the C5s are "bottom feeders";
Go to Pep Boys (or similar) and see if they can do a pressure test of your radiator (especially focusing on the radiator cap);
Air in the radiator system?
Also, when you say "overheat" what temps are you seeing?
Any recent mods to the engine?
Again, I'm sure you will get more great info in the C5 section.
Best wishes for an easy (inexpensive) fix!
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as mentioned make sure your radiator and condensor are free of crap, leaves, plastic bags, dirt...you can try and blow it out with a compressor or wash it out with a hose..amazing how much crap gets up in there on the C5
you may want to remove the air bridge and then remove the upper radiator support to really get in there and flush it all out really good.
also make sure the 2nd fan comes on when the AC comes on
you may want to remove the air bridge and then remove the upper radiator support to really get in there and flush it all out really good.
also make sure the 2nd fan comes on when the AC comes on
Melting Slicks
Joined: Sep 2008
Posts: 3,138
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From: Espanola New Mexico
Yes, make sure your radiator and condenser are clean, free of debris between the fins and such. The AC being on adds more of a heat load to the cars cooling system, so if the cooling system is not operating at optimum efficiency, the temps will rise. The fans of course turn off once the car reaches 35mph, as a powered fan will restrict air flow at highway speeds.
Burning Brakes
Joined: Apr 2002
Posts: 1,105
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From: Lawrenceburg, KY
C5 "NORMAL" OPERATING TEMPERATURE
Fans turn on at 228 for low speed, high speed at 240 or dependant on A/C function and needs.
Your temp could fluctuate up to 240, depending on if you are tracking the car or not.
Your temp could fluctuate up to 240, depending on if you are tracking the car or not.
Melting Slicks
Joined: Nov 2005
Posts: 2,074
Likes: 309
The C5 has two speed cooling fans. The control solenoid can fail so that you get only low speed operation. The solenoid is cheap and easy to replace in the engine compartment and cured a friends car of overheating.
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Pro
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First check to see if anything is blocking the ac condenser up front. Second, your ac compressor could be showing early signs of a failure
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The norm is between 197 and 210 if any higher then people start fircink out even the norm is 215 to 235 stock or somewhere around there. 100 degree im 198 to 207 highest i see.
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I wrote some helpful articles on this since it comes up a lot.
First: Make sure your radiator is clean -- https://c5corvettes.com/tutorials-di...vette-radiator
Second: Check that all of your factory stuff is setup to work as effective as possible, and then consider modifications for additional cooling -- https://c5corvettes.com/features-art...ecommendations
I highly recommend an oil cooler on the C5 corvette. It's easy enough to do yourself and the results are staggering! How to article I wrote: https://www.shredjesse.com/1999-c5-c...diy-oil-cooler
First: Make sure your radiator is clean -- https://c5corvettes.com/tutorials-di...vette-radiator
Second: Check that all of your factory stuff is setup to work as effective as possible, and then consider modifications for additional cooling -- https://c5corvettes.com/features-art...ecommendations
I highly recommend an oil cooler on the C5 corvette. It's easy enough to do yourself and the results are staggering! How to article I wrote: https://www.shredjesse.com/1999-c5-c...diy-oil-cooler