normal coolant temp?
Thread Starter
Racer
Joined: May 2012
Posts: 363
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From: Peabody MA
normal coolant temp?
I just took my '92 coupe on its first road trip through the white mountains of New Hampshire, it ran fine but I noticed the coolant temp was getting above 220 degrees even with the ac on (that turns the fans on right?). If I revved it high for a few minutes or engine-braked my way down a hill it cooled off a bit. I don't know too much about what the coolant temp should be and what is dangerously hot, all I know is that it is usually around 209 degrees. Any info would be appreciated, thanks.
Also, what can I do to make it run a little cooler?
Also, what can I do to make it run a little cooler?
Melting Slicks
Joined: Mar 2008
Posts: 2,351
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From: Delta B.C. Canada
2023 C7 of the Year Finalist - Unmodified
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Check between the rad and the condenser for leaves, trash etc. Also, "burp" your cooling system at the air bleeds.
When was the last time your coolant was flushed and replaced?
When was the last time your coolant was flushed and replaced?
Thread Starter
Racer
Joined: May 2012
Posts: 363
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From: Peabody MA
I honestly have no idea, but I probably should have it done soon. I will try to clean out the radiator as well. I heard about there being a way to make the fans come on at an earlier temp? (190 degrees or so)
Team Owner
Joined: Dec 1999
Posts: 34,873
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From: Lacey WA RVN 68-69
NCM Sinkhole Donor
LT1 C4's are designed to run hotter coolant temp than earlier cars for emissions improvement. IIRC, the factory thermostat is a 195 degree opening and typical coolant temps will run from 195 to 220. Of course a lot depends on the ambient air temps at the time. The secondary fan doesn't even come on until temps hit 238 or when the A/C is on (as you noted).
If you don't know when the last time the cooling system was serviced, it's probably a good time to have it done. Use a good grade of ethylene glycol (green) antifreeze and distilled water in a 50-50 mix. Probably won't hurt to replace the pressure cap.
If you intend to do a lot of your own general maintenance, I highly recommend getting the 2 book set of the Factory Service Manual or FSM. There is a detailed procedure for cooling system flush and refill. You can find them occasionally in the C4 Parts For Sale section or on fleabay.
Tech Contributor
Joined: Oct 2011
Posts: 525
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From: Annapolis MD
'Normal' for me is 197 to 203.
If I am sitting in traffic, I have seen as much as 228, but then the fan comes on and it never gets any higher (only lower).
As others have said, this is normal for this motor.
If I am sitting in traffic, I have seen as much as 228, but then the fan comes on and it never gets any higher (only lower).
As others have said, this is normal for this motor.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
LT1's are a t-stat opening temperature of 180 degrees not 195.
A clean condesnor/radiator area with a good 50/50 mix of Green Coolant/Distilled Water should leave open road temperatures in the low to mid 190's range.
I drove for over 1 hr last weekend one way in 85 degree heat with the A/C on and on the highway with speeds around 45-65MPH. The temperature digital read out went back and forth between 190-193. These cars DO NOT run hot, unless you have issues with the cooling system.
Fans should be on with A/C.
Primary fan on above 219. Secondary fan on above 226. Per my 93 FSM.
Simple solution to the fans coming on later is a manual fan switch. I have one on my car. I pop the primary fan on in town my temps never get above 200 or so if I can help it.
These higher temps. are normal, all modern cars run "hot" good for power, fuel mileage, engine wear, emissions,etc...nothing BAD about it. I'm pretty sure the MOST powerful GM engine EVER made the LS9 with 638HP runs hot, gets better gas mileage, and is emissions compliant compared any cooler running ancient L88 427 big block. Just saying.....
A clean condesnor/radiator area with a good 50/50 mix of Green Coolant/Distilled Water should leave open road temperatures in the low to mid 190's range.
I drove for over 1 hr last weekend one way in 85 degree heat with the A/C on and on the highway with speeds around 45-65MPH. The temperature digital read out went back and forth between 190-193. These cars DO NOT run hot, unless you have issues with the cooling system.
Fans should be on with A/C.
Primary fan on above 219. Secondary fan on above 226. Per my 93 FSM.
Simple solution to the fans coming on later is a manual fan switch. I have one on my car. I pop the primary fan on in town my temps never get above 200 or so if I can help it.
These higher temps. are normal, all modern cars run "hot" good for power, fuel mileage, engine wear, emissions,etc...nothing BAD about it. I'm pretty sure the MOST powerful GM engine EVER made the LS9 with 638HP runs hot, gets better gas mileage, and is emissions compliant compared any cooler running ancient L88 427 big block. Just saying.....
Last edited by 93Rubie; Jun 11, 2012 at 07:44 PM.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,215
From: Park City Utah
I just took my '92 coupe on its first road trip I noticed the coolant temp was getting above 220 degrees even with the ac on (that turns the fans on right?). If I revved it high for a few minutes or engine-braked my way down a hill it cooled off a bit.
Also, what can I do to make it run a little cooler?
Also, what can I do to make it run a little cooler?
BTW fans don't run above 30 mph or so, regardless of control settings. Above that speed there is more than sufficient air flow through the radiator.
Last edited by Tom400CFI; Jun 11, 2012 at 08:38 PM.
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Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,215
From: Park City Utah
LT1's are a t-stat opening temperature of 180 degrees not 195.
A clean condesnor/radiator area with a good 50/50 mix of Green Coolant/Distilled Water should leave open road temperatures in the low to mid 190's range.
I drove for over 1 hr last weekend one way in 85 degree heat with the A/C on and on the highway with speeds around 45-65MPH. The temperature digital read out went back and forth between 190-193. These cars DO NOT run hot, unless you have issues with the cooling system.
A clean condesnor/radiator area with a good 50/50 mix of Green Coolant/Distilled Water should leave open road temperatures in the low to mid 190's range.
I drove for over 1 hr last weekend one way in 85 degree heat with the A/C on and on the highway with speeds around 45-65MPH. The temperature digital read out went back and forth between 190-193. These cars DO NOT run hot, unless you have issues with the cooling system.
Thread Starter
Racer
Joined: May 2012
Posts: 363
Likes: 0
From: Peabody MA
Thank you so much everyone, I really appreciate the help and advice, I'm new to all this stuff! 
I'm going to look for one of those fsm books, seems like a pretty essential thing to have
I'm going to look for one of those fsm books, seems like a pretty essential thing to have