C5 Engine OverHeating
Thread Starter
1st Gear
Joined: Oct 2003
Posts: 1
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From: Crystal Lake il
C5 Engine OverHeating
While running at the track doing high speed, I am encountering high engine coolant temps. Temps in the area of 240 degrees after running for 15 minutes. I have look at obstructions, change to a 180 degree thermostat, put in additives. Any ideas?
Last edited by jrhot; Sep 2, 2005 at 03:57 PM.
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
take a high pressure air hose and blow out the sand, dirt, grass and any other road clagg that may be in there. The radiator may look clean, but does not mean it is.
I clean my radiator out between track events and get out at least two hand fulls of clagg. Great for filling pot holes in the driveway.
Next when did you last flush your radiator ?? that can help too.
I clean my radiator out between track events and get out at least two hand fulls of clagg. Great for filling pot holes in the driveway.
Next when did you last flush your radiator ?? that can help too.
Intermediate
Joined: Apr 2005
Posts: 32
Likes: 0
see if the fan is coming on by looking. Make sure the coolant level is full. Maybe the thermostat is bad. The water pump may not be operating correctly. Last check for hydrocarbons in the coolant. You can get testing materials at parts stores. The presence of hydrocarbons would indicate a possible bad head gasket or possibly a cracked head or block. This makes motors overheat.
Le Mans Master
Joined: Jun 2004
Posts: 6,269
Likes: 50
From: Dallas Texas
St. Jude Donor '06-'07-'09-'10
Originally Posted by AU N EGL
take a high pressure air hose and blow out the sand, dirt, grass and any other road clagg that may be in there. The radiator may look clean, but does not mean it is.
I clean my radiator out between track events and get out at least two hand fulls of clagg. Great for filling pot holes in the driveway.
Next when did you last flush your radiator ?? that can help too.
I clean my radiator out between track events and get out at least two hand fulls of clagg. Great for filling pot holes in the driveway.
Next when did you last flush your radiator ?? that can help too.
With a bottom breathing cooling system, the C5 picks up everything that's loose. If you look up from under the front end, you see the A/C condenser. The radiator is behind it and both need cleaning. You'd be amazed at the amount of stuff that gets stuck in the fins 
Le Mans Master
Joined: Sep 1999
Posts: 7,393
Likes: 7
From: Los Angeles CA
Originally Posted by jrhot
While running at the track doing high speed, I am encountering high engine coolant temps. Temps in the area of 240 degrees after running for 15 minutes. I have look at obstructions, change to a 180 degree thermostat, put in additives. Any ideas?
Tech Contributor
Joined: Oct 1999
Posts: 40,995
Likes: 9,759
From: Charlotte, NC (formerly Endicott, NY)
Low temp thermo will not solve the problem since the 195 is fully open at the temps you are seeing and all the low temp thermo will do is slightly slow down the rate of temperature increase. Having the fans on at high speed may actually be worse since they will not free wheel and could slow down air movement.
More critical what is your oil temp at those speeds? Check your coolant level to make sure it is all the way up. Just a small shortage can raise the temps. The C5 cooling system is marginal when operated at WOT for long periods and just barely gets the heat out of the engine.
Make sure there are no obstructions in the air flow through the A/C condensor and radiator and also make sure the seals between the radiator shroud and the A/C condensor are in place and in good shape. If they have blown out a lot of air is just blowing by the A/C condensor & radiator instead of going through them.
Bill
More critical what is your oil temp at those speeds? Check your coolant level to make sure it is all the way up. Just a small shortage can raise the temps. The C5 cooling system is marginal when operated at WOT for long periods and just barely gets the heat out of the engine.
Make sure there are no obstructions in the air flow through the A/C condensor and radiator and also make sure the seals between the radiator shroud and the A/C condensor are in place and in good shape. If they have blown out a lot of air is just blowing by the A/C condensor & radiator instead of going through them.
Bill
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Originally Posted by Bill Dearborn
Make sure there are no obstructions in the air flow through the A/C condensor and radiator and also make sure the seals between the radiator shroud and the A/C condensor are in place and in good shape. If they have blown out a lot of air is just blowing by the A/C condensor & radiator instead of going through them.
Bill
Bill
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Melting Slicks
Joined: Nov 2004
Posts: 3,495
Likes: 0
From: Paducah Ky
While changing my oil the other day I looked up at radiator fins and had a line of grass and a cellophane wrapper off a pack of cigs stuck in there. My car has less than 16,000 miles and was surprised how much stuff was stuck on there, much less what may actually be inside it. I agree with the above, simply blowing out may surprise you how much junk's in there.