Coolant temp question
Thread Starter
Pro
Joined: Nov 2000
Posts: 703
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From: Cypress Texas
Coolant temp question
After reading through all of the other recent posts I can find about coolant temps, I didn't see this particular problem mentioned.
I have an '04 Coupe and have not done any new maintenance/work to it lately. I noticed the coolant temp stayed a little higher then normal while being stuck in traffic, the temp hovered around 239-240. It didn't seem to get any hotter, but immediately dropped as it should once I started driving.
I let the car idle in the garage to make sure the fans came on at the proper temp and they did. However, the coolant temp hovered around 239-240 and was not coming down with the fans running on high. The strange part is that I revved the motor and the temperature immediately dropped to 220 and then did not seem to creep back up as it did earlier.
Any advice on where to start with this one ?
Thanks,
Ernie
I have an '04 Coupe and have not done any new maintenance/work to it lately. I noticed the coolant temp stayed a little higher then normal while being stuck in traffic, the temp hovered around 239-240. It didn't seem to get any hotter, but immediately dropped as it should once I started driving.
I let the car idle in the garage to make sure the fans came on at the proper temp and they did. However, the coolant temp hovered around 239-240 and was not coming down with the fans running on high. The strange part is that I revved the motor and the temperature immediately dropped to 220 and then did not seem to creep back up as it did earlier.
Any advice on where to start with this one ?
Thanks,
Ernie
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From: Phoenix area, AZ
Last edited by Corvette_Ed; Dec 29, 2013 at 02:53 PM.
Melting Slicks
Joined: Sep 2011
Posts: 2,256
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From: Appleton WI
Cleaning the radiator and condenser is a good thing to do and cheap but I don't think that is the problem. If air flow was a problem, neither the fans or vehicle speed should help cool the engine. The fans shut off above a certain speed and air is forced through the radiator by the air dam.
To me, it sounds more like a circulation problem like low coolant, stuck thermostat (doesn't open fully), or failing pump. Has your car overheated in the recent past or had a coolant leak? You may be low on coolant. The big clue you provided is the temperature change after revving the engine. This act increased the coolant flow. Revving the engine will not increase air flow. Your fans are electric.
To me, it sounds more like a circulation problem like low coolant, stuck thermostat (doesn't open fully), or failing pump. Has your car overheated in the recent past or had a coolant leak? You may be low on coolant. The big clue you provided is the temperature change after revving the engine. This act increased the coolant flow. Revving the engine will not increase air flow. Your fans are electric.
Last edited by 3sACROWD; Dec 29, 2013 at 03:57 PM.
Thread Starter
Pro
Joined: Nov 2000
Posts: 703
Likes: 2
From: Cypress Texas
Cleaning the radiator and condenser is a good thing to do and cheap but I don't think that is the problem. If air flow was a problem, neither the fans or vehicle speed should help cool the engine. The fans shut off above a certain speed and air is forced through the radiator by the air dam.
To me, it sounds more like a circulation problem like low coolant, stuck thermostat (doesn't open fully), or failing pump. Has your car overheated in the recent past or had a coolant leak? You may be low on coolant. The big clue you provided is the temperature change after revving the engine. This act increased the coolant flow. Revving the engine will not increase air flow. Your fans are electric.
To me, it sounds more like a circulation problem like low coolant, stuck thermostat (doesn't open fully), or failing pump. Has your car overheated in the recent past or had a coolant leak? You may be low on coolant. The big clue you provided is the temperature change after revving the engine. This act increased the coolant flow. Revving the engine will not increase air flow. Your fans are electric.
I will certainly clean out the radiator/condenser regardless, but was thinking along the same lines as far as a coolant flow issue. Do these water pumps have a "weep hole" like the old SBC pumps used to have ? I will more than likely replace the thermostat as well, but am definitely open and appreciative of all advice.
Thanks,
Ernie
Tech Contributor
Joined: Jan 2004
Posts: 20,030
Likes: 289
From: Wylie TX --> Less is More, except under the hood !
From what I have read on the forum in the past. You want to be around 190-210 on coolant temp (optimum)
In the summer when it was 100F and humid as crap...
I was getting my safety inspection done.
My car was idling in the safety check bay place for 30 mins, and never got over 217F.
Once I started driving it came back down to normal operating temps.
I would start by cleaning out your radiator and condenser really well.
Water and or Air work well.
Consider a coolant flush.
Verify your fans are operating, .... and operating normally.
Make sure that you don't have any debris up the air intake area under the car.
Make sure that your air dam under the car is angled correctly to force air up into the radiator area. If its not aimed correctly I have seen over temp issues.
To me your temp is running WAY high...
I'm not a certified engine tech though....
Toque
Good advice Ed.... .
In the summer when it was 100F and humid as crap...
I was getting my safety inspection done.
My car was idling in the safety check bay place for 30 mins, and never got over 217F.
Once I started driving it came back down to normal operating temps.
I would start by cleaning out your radiator and condenser really well.
Water and or Air work well.
Consider a coolant flush.
Verify your fans are operating, .... and operating normally.
Make sure that you don't have any debris up the air intake area under the car.
Make sure that your air dam under the car is angled correctly to force air up into the radiator area. If its not aimed correctly I have seen over temp issues.
To me your temp is running WAY high...
I'm not a certified engine tech though....
Toque
I'd start by cleaning out the radiator and condenser.
http://www.toquez06.com/radiator.html
http://www.toquez06.com/radiator.html
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Le Mans Master
Joined: Dec 2000
Posts: 5,245
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From: Blue Ridge Georgia
I've done two different methods. You can just get your garden hose with a good nozzle and lay down in front to the car a spray like hell. You might be able to scrap some crude off my hand before your spray. I've also used compressed air nozzle to spray the crude out. You going to flip out when you see how much crude is there. Last method is to pull the rad.
Melting Slicks
Joined: May 2008
Posts: 2,606
Likes: 355
From: Rochester New York
240* is very close to over heating. The fact that it cooled down when you revved the motor may indicate a coolant flow problem. Like the others have said, check the radiator and condenser fins for dirt, leaves, grass, etc...
Since you have not done so, a coolant flush would not be a bad idea, maybe replace the thermostat (it's very simple) for a little insurance.
Since you have not done so, a coolant flush would not be a bad idea, maybe replace the thermostat (it's very simple) for a little insurance.
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Burning Brakes
Joined: Dec 2003
Posts: 1,243
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From: Loveland CO
Mine gets up near that hot on a HOT day, bottom feeders do tend to run warm. I cleaned my AC/Radiator, replaced my T-stat/Waterpump (leaking) and still get up there when in stop and go traffic.
A slightly cooler T-stat will help, Stock is 186*. If you live in a area that gets cool might wanna stick with a stock 186* stat or Drilling a stock stat (Small hole allowing some coolant to flow past when closed) Also if you have your car tuned the tuner can adjust the fan temp so they come on sooner and stay on longer. IF you do thoes things and still run hot then time for a Dewitts or Ron Davis Radiator, they will cool much better then stock.
A slightly cooler T-stat will help, Stock is 186*. If you live in a area that gets cool might wanna stick with a stock 186* stat or Drilling a stock stat (Small hole allowing some coolant to flow past when closed) Also if you have your car tuned the tuner can adjust the fan temp so they come on sooner and stay on longer. IF you do thoes things and still run hot then time for a Dewitts or Ron Davis Radiator, they will cool much better then stock.
Last edited by RedZMonte; Jan 2, 2014 at 06:34 PM.
Race Director
Joined: May 2012
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From: Phoenix area, AZ
Mine gets up near that hot on a HOT day, bottom feeders do tend to run warm. I cleaned my AC/Radiator, replaced my T-stat/Waterpump (leaking) and still get up there when in stop and go traffic.
A slightly cooler T-stat will help, Stock is 186*. If you live in a area that gets cool might wanna stick with a stock 186* stat or Drilling a stock stat (Small hole allowing some coolant to flow past when closed) Also if you have your car tuned the tuner can adjust the fan temp so they come on sooner and stay on longer. IF you do thoes things and still run hot then time for a Dewitts or Ron Davis Radiator, they will cool much better then stock.
A slightly cooler T-stat will help, Stock is 186*. If you live in a area that gets cool might wanna stick with a stock 186* stat or Drilling a stock stat (Small hole allowing some coolant to flow past when closed) Also if you have your car tuned the tuner can adjust the fan temp so they come on sooner and stay on longer. IF you do thoes things and still run hot then time for a Dewitts or Ron Davis Radiator, they will cool much better then stock.
Just fyi, the stock thermostat is 187*, not 186*.
Race Director
Joined: Apr 2007
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From: South Western Ontario
You're saying it should never reach 239*? It's got to hit at least 235* to get the fans to high speed so climbing a few more degrees to 239* isn't much of a stretch. Not dropping with the high fans is indicative of dirt in the rad, but you could install a brand new rad and it would still have to climb to 235* before the high speed fans engage to cool it.
Burning Brakes
Joined: Dec 2003
Posts: 1,243
Likes: 5
From: Loveland CO
As i stated in my post, My WP was leaking so i replaced it all and still didnt change the temp the car got up to on a hot day in traffic. My radiator was nut gunked up but i cleaned it anyhow (some dirt and junk but not much). Vette's are Bottom Feeders run hot when the car is not moving. Again the only way to cool them down (Assuming the cooling system is working correctly) is to Adjust fans in the tune and/or upgrade the radiator. The C5 radiator is not great if you are in warmer/hot climates or are heavily modified especially in stop and go traffic.
S
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Joined: May 2012
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From: Phoenix area, AZ
Even with the triple-digit temps during a typical Texas summer my car never gets hotter than 220 while not moving.
No, it is not the only way to run cool. I live in one of those hot climates, see 100+ temps regularly during summer months, and have no need to have my fans adjusted. I also don't need an overpriced radiator to achieve nominal operating temps.
No, it is not the only way to run cool. I live in one of those hot climates, see 100+ temps regularly during summer months, and have no need to have my fans adjusted. I also don't need an overpriced radiator to achieve nominal operating temps.