C4 Over heating
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C4 Over heating
I have a rebuilt engine (less than 3000 miles), that over heats. I have flushed the cooling system, checked both fans, replaced water pump, replaced thermos stat, fan switch, radiator cap, and the fan relay. I have also added some 20 degree below to the cooling system. But, when I use the A/C, the temp. quickly easies up the 240 degrees plus. What have I missed, other than checking the timing? Could the timing cause that much of a heating problem? When it's a 100+ degrees outside, the car runs fine, until I use the A/C.
Le Mans Master
Joined: Feb 2006
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From: Louisiana
Originally Posted by Sirwilliam1229
I have a rebuilt engine (less than 3000 miles), that over heats. I have flushed the cooling system, checked both fans, replaced water pump, replaced thermos stat, fan switch, radiator cap, and the fan relay. I have also added some 20 degree below to the cooling system. But, when I use the A/C, the temp. quickly easies up the 240 degrees plus. What have I missed, other than checking the timing? Could the timing cause that much of a heating problem? When it's a 100+ degrees outside, the car runs fine, until I use the A/C.
I don't know what year vette we are taking about and profile is blank so the info I give will be general. Make sure the area is clean between the radiator and A/C condensor. Make sure all the air is out of the coolant system and that the fan(s) is/are working and at what temp it/they come on. If the timing is off enough it can make an engine run hot. If you question the timing, double check it to see where your at and make sure the distrubitor bolt is tight.
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The first question you need to ask is "is it truely over heating? I kno the cooling fan doesn't come on in my vette until 255.
Also 212 is not overheating. we're talking a closed pressurized system.
Which allows for much higher temps.
You say overheating does that mean boiling over? Stuck on the side of the road?
Or I think it's running hot?
Have you replaced the temp sending unit? It may be just that easy
Also 212 is not overheating. we're talking a closed pressurized system.
Which allows for much higher temps.
You say overheating does that mean boiling over? Stuck on the side of the road?
Or I think it's running hot?
Have you replaced the temp sending unit? It may be just that easy
Team Owner
Joined: Sep 2001
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From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
If the overheating is AC related, you'd probably be best asking SunCr
I believe if the pressures are too high then extra heat would be imparted to the condensor.
any other overheating solutions are on my website
I believe if the pressures are too high then extra heat would be imparted to the condensor.
any other overheating solutions are on my website
Melting Slicks
Joined: Apr 2000
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From: Bel Air Md
OK, here is my .02. RRT made a good point about the area between the radiator and condenser. You can get a ton of junk in there. My 93 has an open space at the bottom to check but the L98's were sealed. One thing I did read about the LT1 is the correct thermostat. If it is a 92-96 just any thermostat won't work. There is something special, can't remember what , in the design of the thermostat for an LT1.
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From: Northern, VA
St. Jude Donor '15
"In honor of jpee"
Rather than everyone shooting in the dark, so to speak, why don't you give us a few more details about the car. Mileage, year, motor, modifications, where you are with the car (geog), trans, condition, what else you've done/tried, thermostat, etc. Thanks.
Drifting
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From: the passing lane, SO MOVE IT!!!!
CI 2-3-4-5-6-7-8-9-10-11-12 Vet
St. Jude Donor '06
Have you ever pulled the raidator out of the car? The C4's are known for sucking up all kinds of debris. You will have all kinds of sand, leaves, animal fur in even a low mile car. Reasearch the archives as there has been plenty of posts about flushing the outside of the radiator. My ride has 40K on it and it needed too be done. Good luck!
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I have 164K on the car, and I rebuilt the engine less than 3000 miles ago. I have a 160 degree thermo stat, I have not pulled the radiator, ummm what else? The car is a 1989 with an automatic trans, Hypertech chip, borla exhaust, K&N filter with an open lid, and a useless air foil. I live in Southern California, where the temps. lately have stayed between 102-117 degrees.
Pro
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From: TEMECULA CALIFORNIA
St. Jude Donor '06-'07-'08-'09
Do Your Analog And Digital Temps Match?
My Guess Either Junk On The O/s Of The Radiator, Or Junk Loose In The Inside Of The Radiator. Pull That Baby And Clean, Or Replace.
My Guess Either Junk On The O/s Of The Radiator, Or Junk Loose In The Inside Of The Radiator. Pull That Baby And Clean, Or Replace.
Not unless you reprogrammed the ECM or PCM.
Team Owner
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From: Athens AL
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Originally Posted by Sirwilliam1229
I have 164K on the car, and I rebuilt the engine less than 3000 miles ago. I have a 160 degree thermo stat, I have not pulled the radiator, ummm what else? The car is a 1989 with an automatic trans, Hypertech chip, borla exhaust, K&N filter with an open lid, and a useless air foil. I live in Southern California, where the temps. lately have stayed between 102-117 degrees.
Cruising
Joined: Jun 2006
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From: Virginia Beach VA
Before you decide that it is overheating, you should compare the digital sensor output with the analog guage output. They take readings from two different locations on the engine. Second, when your A/C is on you should notice thgat your second cooling fan runs, if it doesn't this could be your problem.
Le Mans Master
Joined: Oct 2003
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From: seattle WA
All good advice. As for ToolBox and his 87, you've got problems. The aux. fan on an 87 should be comming on at around 236-238, and if you're hitting temps of 255, hope your using synthetic oil, and start saving money for a new engine.
Safety Car
Joined: May 1999
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From: Atlantis
Cruise-In I Veteran
My '91 has been running 240*~ 250* on 100* days.
I've cleaned between the condensor and the radiator, removed the radiator and cleaned it.
It's full of water. It has ALWAYS run hot in the summer.
My '84 typically runs 220*~230* on the same day. I've done all the same cleaning to the radiator on it as well.
It seems the cooling system is marginal at best.
Both of them run hotter than I'd like but... I just don't worry about it anymore.
1) I've run Water Wetter .... NO Change in temps.
2) I've run 40? Below ...... No Change In Temps.
3) I've run Greased Lightning Cooling System Treatment....No Change In Temps
4) I've run 20% Coolant & 80%* Water..... No Change In Temps
I've cleaned between the condensor and the radiator, removed the radiator and cleaned it.
It's full of water. It has ALWAYS run hot in the summer.
My '84 typically runs 220*~230* on the same day. I've done all the same cleaning to the radiator on it as well.
It seems the cooling system is marginal at best.
Both of them run hotter than I'd like but... I just don't worry about it anymore.
1) I've run Water Wetter .... NO Change in temps.
2) I've run 40? Below ...... No Change In Temps.
3) I've run Greased Lightning Cooling System Treatment....No Change In Temps
4) I've run 20% Coolant & 80%* Water..... No Change In Temps