Cooling Temp Hot...
Thread Starter
Instructor
Joined: May 2004
Posts: 240
Likes: 0
From: Bay Area CA
Cooling Temp Hot...
Hey guys, I have a 2004 Coupe and my cooling temp reached 245 degrees, no leaks, replaced both belts, water pump has no play in it. Took out the thermostat, seems to be ok when you boil it in hot water on the stove, it definately opens up. I checked for debris inside the radiator and it all looks clear. I left out the stat and drove it and it still gets up to 245 degrees
I want to know what else I might need to do. 76k on the original dex-cool! Any suggestions would be appreciated 
I want to know what else I might need to do. 76k on the original dex-cool! Any suggestions would be appreciated
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Hey guys, I have a 2004 Coupe and my cooling temp reached 245 degrees, no leaks, replaced both belts, water pump has no play in it. Took out the thermostat, seems to be ok when you boil it in hot water on the stove, it definately opens up. I checked for debris inside the radiator and it all looks clear. I left out the stat and drove it and it still gets up to 245 degrees I want to know what else I might need to do. 76k on the original dex-cool! Any suggestions would be appreciated
I want to know what else I might need to do. 76k on the original dex-cool! Any suggestions would be appreciated The C5 is a bottom feeder, air is deflected up into the ac condenser, then through it to the radiator directly behind it.. I would have the surge cap tested or replaced, I would change the dex-cool, and I would remove the upper radiator shroud to expose the top of the condenser and the radiator.. With a blow pipe blow from the back toward the front of the car.. the radiator first and then the condenser.. you will see a half cup of bug guts, fuzzies, all types of leaf particles, and sand and road grime, which get into both sets of cooling vanes.
Bill aka ET
Race Director
Joined: Jan 2006
Posts: 10,554
Likes: 33
From: Not on either liberal coast.
And put the thermostat back in. I don't watch my coolant temperatures on the DIC, but I do watch the oil temperatures routinely and leave that displayed instead of the odometer.If leaves, plastic bags are an issue with your car, you can DIY or buy a bug screen to cover the bottom opening beneath your radiator/condenser. It won't stop bug guts and dust though. Many use the product from ELITE ENGINEERING. Otherwise, cleaning that area as mentioned needs to become a routine maintenance project.
In slow mountain traffic, in a lower gear/higher rpm, my car's oil temperature has gone as high as 242 in AZ summer. As soon as I was able to get away from traffic and shift into a higher gear, the temperatures dropped back down to the 220 range.
Your fans don't even come on until 226 and 235 degrees, otherwise the coolant system relies strictly on the incoming air flow. And if I'm not mistaken, at a certain speed the fans turn off. If I recall correctly (?), you can even drive your C5 w/o coolant for a certain distance by design. The LSx motor is amazing in it's engineering.
E-T could elaborate on that. FYI, E-T was an engineer on the C5 Corvette. ..
Last edited by hotwheels57; Jun 11, 2010 at 07:08 PM.
Instructor
Joined: Feb 2010
Posts: 202
Likes: 0
From: The Chi
And put the thermostat back in. I don't watch my coolant temperatures on the DIC, but I do watch the oil temperatures routinely and leave that displayed instead of the odometer.If leaves, plastic bags are an issue with your car, you can DIY or buy a bug screen to cover the bottom opening beneath your radiator/condenser. It won't stop bug guts and dust though. Many use the product from ELITE ENGINEERING. Otherwise, cleaning that area as mentioned needs to become a routine maintenance project.
In slow mountain traffic, in a lower gear/higher rpm, my car's oil temperature has gone as high as 242 in AZ summer. As soon as I was able to get away from traffic and shift into a higher gear, the temperatures dropped back down to the 220 range.
Your fans don't even come on until 226 and 235 degrees, otherwise the coolant system relies strictly on the incoming air flow. And if I'm not mistaken, at a certain speed the fans turn off. If I recall correctly (?), you can even drive your C5 w/o coolant for a certain distance by design. The LSx motor is amazing in it's engineering.
E-T could elaborate on that. FYI, E-T was an engineer on the C5 Corvette. ..
Le Mans Master
Joined: Feb 2003
Posts: 6,683
Likes: 144
From: Memphis Tennessee
I am not totally clear on the circumstances that are causing your higher temp readings. BUT, you will see lower temperatures if you run the AC when moving slow in traffic. Running the AC turns on the "low speed" fan to help move air across the condensor, and obviously the radiator.
Being a "bottom feeder" and not having a water-pump driven fan, you will see high temps with no AC, slow or standing speed or high rpm driving.
Now, on to your OLD coolant. I would do a serious flush. I changed mine at 36K and it looked new. But, the recommended interval is 30K and you are on your THIRD full interval without a change. Reports have it that some blockage can occur with old or imporperly mixed coolants. Simple to do, so take care of it soon. JMHO
Being a "bottom feeder" and not having a water-pump driven fan, you will see high temps with no AC, slow or standing speed or high rpm driving.
Now, on to your OLD coolant. I would do a serious flush. I changed mine at 36K and it looked new. But, the recommended interval is 30K and you are on your THIRD full interval without a change. Reports have it that some blockage can occur with old or imporperly mixed coolants. Simple to do, so take care of it soon. JMHO
Instructor
Joined: Oct 2007
Posts: 163
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From: Reston Manitoba
I think you can...the computer goes into "limp" mode and cycles which cylinders receive an ignition spark to manage engine temperature. Temperature of individual cylinders are controlled so engine damage will not/should not occur.
Instructor
Joined: Feb 2010
Posts: 202
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From: The Chi
I'm draining coolant as we speak.
I kid I kid
Drifting
Joined: Nov 2006
Posts: 1,682
Likes: 2
From: Plano Texas
St. Jude Donor '08
So did you clean out the condenser or the radiator? the condenser is what you see as you look up under the car.
I had 2 problems causing high temps on mine. I was seeing 240-250 in the texas summer in town. First was debris in the radiator fins. You need to get in between the condenser and radiator and really clean it all out well. Second was I had a fan out. My left most fan was not coming on (bad fan motor).
Eventually I just ended up getting a dewitts radiator and dual fan upgrade and the most I see now is 190-195, even on a 100 degree day. My fan kicks on at 190, and those things really move some air.
I had 2 problems causing high temps on mine. I was seeing 240-250 in the texas summer in town. First was debris in the radiator fins. You need to get in between the condenser and radiator and really clean it all out well. Second was I had a fan out. My left most fan was not coming on (bad fan motor).
Eventually I just ended up getting a dewitts radiator and dual fan upgrade and the most I see now is 190-195, even on a 100 degree day. My fan kicks on at 190, and those things really move some air.
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Race Director
Joined: Jan 2006
Posts: 10,554
Likes: 33
From: Not on either liberal coast.
I can't find the discussion with C5 engineer "Evil-Twin" from 3-4+ years ago. I remember a thread in which he described the limp home mode and that the LSx motor could be driven for a short distance with a complete loss of coolant. I could be mistaken in my memory of his comments, hence the (?) in my reply above.
Maybe Evil-Twin will chime in with his first hand knowledge.
I did find this reference in the C5/Z06 owners manual but it doesn't mention complete loss of coolant...
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
messages COOLANT OVER TEMP and REDUCED
ENGINE POWER are displayed, along with the Check
Engine light, an overheat protection mode which
alternates firing groups of cylinders helps prevent engine
damage. In this mode, you will notice a loss in power
and engine performance. This operating mode
allows your vehicle to be driven to a safe place in an
emergency; you may drive up to 50 miles (80 km).
Notice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the
cause of coolant loss, change the oil and reset the oil
life system. See Engine Oil on page 5-13.
5-
Last edited by hotwheels57; Jun 12, 2010 at 05:38 PM.
Burning Brakes
Joined: Sep 2007
Posts: 759
Likes: 50
From: woodbridge,VA Myrtle Beach,SC
complete loss of coolant, and no spark no fuel,just pumps air, in every other firing cylinder is the Northstar Cad. motor, tested in Death Valley 360 miles.and 112+ degrees.
limp mod in the LS motor is for over heated coolant, NOT loss. car will lock up if coolant loss!
limp mod in the LS motor is for over heated coolant, NOT loss. car will lock up if coolant loss!
Thread Starter
Instructor
Joined: May 2004
Posts: 240
Likes: 0
From: Bay Area CA
Hey fellow members, Thakyou to everyone with their input with my overheating problem.
I changed the surge tank Cap, flushed and filled with new Dex-Cool, new Stat too!
Seems to be better than before running 210-220deg. but yesterday going through the mountains with outside temp pushing 100deg., She hit 235 a few times while climbing a grade. Maybe this is normal for California summer driving.
I changed the surge tank Cap, flushed and filled with new Dex-Cool, new Stat too!
Seems to be better than before running 210-220deg. but yesterday going through the mountains with outside temp pushing 100deg., She hit 235 a few times while climbing a grade. Maybe this is normal for California summer driving.
Tech Contributor
Joined: Jan 2007
Posts: 19,465
Likes: 1,166
From: Dyer, IN
complete loss of coolant, and no spark no fuel,just pumps air, in every other firing cylinder is the Northstar Cad. motor, tested in Death Valley 360 miles.and 112+ degrees.
limp mod in the LS motor is for over heated coolant, NOT loss. car will lock up if coolant loss!
limp mod in the LS motor is for over heated coolant, NOT loss. car will lock up if coolant loss!
USMC (retired)
Joined: Aug 2004
Posts: 3,268
Likes: 7
From: Wimauma FL
part of maintenance
As this post shows, I was very surprised at what came out when we replaced the radiator.
I suggest that this be part of the bi annual maintenance
http://forums.corvetteforum.com/sout...-the-wise.html
I suggest that this be part of the bi annual maintenance
http://forums.corvetteforum.com/sout...-the-wise.html
