Questions about overheating.....
Thread Starter
Pro
Joined: Oct 2006
Posts: 609
Likes: 0
From: Kentucky
Questions about overheating.....
I have a 98' corvette just noticed a spike in temps. I drove on the interstate at about 70 and the coolant temp rose to 240. Also my transmission temp is a little high, reaching 240 as well. Whats the problem?
Any advice is appreciated. I do have a new radiator and reservoir with ac turned off.
Any advice is appreciated. I do have a new radiator and reservoir with ac turned off.
Drifting
Joined: Jul 2007
Posts: 1,365
Likes: 1,818
If you have a new radiator then there is likely air trapped in the system and it needs to be burped. Could also be a bit low on coolant. Trans temp would likely get hot because the fluid flows through one of the radiator tanks to be cooled and the radiator is hot. Get the engine/radiator temp down and the trans temp should follow it.
Here's a burp procedure that I have used successfully. Copied it from a post some time ago:
'
Start w/ a cold engine
Remove rad. cap
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Start engine
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Top off
I have repeated the process a couple of times on at least 1 car to get enough trapped air out.
You should also make sure that both fans are running when the engine temp gets above 225 and the car is not moving. Fans go off above 35MPH so they would not be running at the highway speeds you mentioned. Air flow through the radiator should be adequate too cool at highway speeds. Also check the pressure cap to make sure the rubber seal is not rotted and leaking pressure. Replacement caps are 18 lbs rather than the 15 the OEM one was.
Is the center section of the front air dam in place? It is gone on many cars but it is an integral part of the GM design to force adequate air up through the radiator to effect cooling. If yours is gone you should consider replacing it cause it does help cooling......
Here's a burp procedure that I have used successfully. Copied it from a post some time ago:
'
Start w/ a cold engine
Remove rad. cap
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Start engine
Idle for 1 minute
Install cap
Cycle RPM from idle to 3000 until coolant reaches 210F
Shut off engine
Remove cap
Top off
I have repeated the process a couple of times on at least 1 car to get enough trapped air out.
You should also make sure that both fans are running when the engine temp gets above 225 and the car is not moving. Fans go off above 35MPH so they would not be running at the highway speeds you mentioned. Air flow through the radiator should be adequate too cool at highway speeds. Also check the pressure cap to make sure the rubber seal is not rotted and leaking pressure. Replacement caps are 18 lbs rather than the 15 the OEM one was.
Is the center section of the front air dam in place? It is gone on many cars but it is an integral part of the GM design to force adequate air up through the radiator to effect cooling. If yours is gone you should consider replacing it cause it does help cooling......
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Might want to check the area in front of the radiator and make sure there is no debris in there - the C5 is known for sucking all sorts of stuff up into that area and blocking airflow.
Melting Slicks
Joined: Jan 2002
Posts: 2,754
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From: Nokomis FL
The C5 acts like a large vacuum cleaner especially if you drive on a grassy field. I found enough to make a birds nest and a McDonalds wrapper in mine after one outing.
Racer
Joined: Dec 2005
Posts: 321
Likes: 3
From: bloomington Indiana
I just replaced the thermostat in my 99 vert with 99k miles. The operating temps just gradually increased over the last year. Finally after reaching 230, I changed the thermostat and everything is back to around 195.
I tried cleaning out the rad fins but it didn't help lower the temps.
I tried cleaning out the rad fins but it didn't help lower the temps.
Thread Starter
Pro
Joined: Oct 2006
Posts: 609
Likes: 0
From: Kentucky
I just replaced the thermostat in my 99 vert with 99k miles. The operating temps just gradually increased over the last year. Finally after reaching 230, I changed the thermostat and everything is back to around 195.
I tried cleaning out the rad fins but it didn't help lower the temps.
I tried cleaning out the rad fins but it didn't help lower the temps.
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Racer
Joined: Dec 2005
Posts: 321
Likes: 3
From: bloomington Indiana
Thermostat is located in the water outlet housing on the right front (passenger side & large diameter hose) of the motor. It is an integral part/assembly with the outlet housing. It has (2) 10mm hex head bolts holding it in place.
Found my replacement at AutoZone (MotoRad for $20 + tax).
Found my replacement at AutoZone (MotoRad for $20 + tax).
Burning Brakes
Joined: Nov 2008
Posts: 764
Likes: 0
From: Arden NC
I've seen everything up in there. Newspaper, sand, flattened out aluminum can and a lot of other debris that will hinder the performance of the cooling system.
JOE
