I have an '03 corvette and it hs been overheating. Sometimes it runs fine and sometimes the temp will jump from 220 to 230 or 240 degrees. Usually i turn on the heat for a minute and the temp goes right back down. Sometimes it goes up and down for a couple minutes and then runs fine. Sometimes it will run all day without this problem and sometimes as soon as it gets hot it stays that way till i turn it off. Does anyone have any suggestions? It was running with almost no coolant for a couple days but i refilled it and it worked fine for almost a week before the overheating problems started again. Now it is holding fluid just fine but still giving me problems.

 

If you lost a lot of coolant, you should really try to find where it leaked from. That's probably the cause of your car running hot. It's supposed to be a closed system, so where ever it is leaking probably takes in air on occasion and that might be why it only runs hot sometimes.

Check hoses and look around the water pump for stains, or coolant.

 

Thanks. Ill try that. What is the damage being done by my car running 230 or 240 degrees for short periods of time like it is. Is this something that my car can deal with till winter or is it doing to much damage to continue driving in this condition?

 

Are you running the A/C at all during the hot temps? Are you going by the analog gauge or the DIC? What kind of driving conditions ie freeway, heavy traffic etc? Also if you just refilled the radiator what mix did you use? If you didn't you might check it with a coolant tester($6) and read the boiling point. The boiling point for coolant is lower than water so if the mix if off (more coolant than water) then it will run hotter. Have you checked to make sure cooling fans are coming on? That can be done by turning off heat and ac look uunder the hood, if it's spinning turn on A/C and see if you can hear the click of the relay and fans speed up.

If you do a search on the forums it's pretty common during the summer months for the car to reach high temps around 229*. If it's hitting 240+ with the A/C running then I would look into a sticking thermostat, fan relays.

 

These cars are sensitive to air in the system. Search the forum on how to properly "burp" the system. Also, clean the crud out of the radiator...that would be the intake side near the road--could have dirt, plastic bags, deceased insects, etc.

 

Sometimes i think running the a/c causes it to run hotter. But sometimes i leave the air blasting all day and it doesnt give me any problems. Usually once i turn the heat on it takes less than 10 - 20 seconds before the temp goes right back down to 220. And im reading the temp right off of the dash while im driving. Im usually driving in a decent amount of traffic but it overheats on the highway sometimes too. I did fill it up with the wrong coolant. I used the green 50/50 mix from the gas station, but i think it had pretty much evaporated all of the old coolant out because it took over a jug of the green coolant to fill it back up.

 

The capacity is 12.6qts or about 3gal. The down side is I'm willing to bet that unless you have a coolant leak some where in the engine itself your gonna have to take it to a shop to have a coolant flush done. There is still coolant in the passages, water pump hoses, heater core etc when the radiator is bone dry. Mixing old school green with Dex-col is a bad idea that can wreck engine seals and form a build up that can clog passages, water pump heater core, radiator etc.

Hope this helps,
Brandon

 

First of all, if you have a shop manual and a hose it is very easy to flush the engine yourself. The manual also states not to use a chemical flush, just use water. You shouldn't mix coolant types, so you should do this. My first suggestion I always recommend is to clean out the radiator and a/c cores. They can hold alot of dirt which will reduce your cooling an incredible amount. After just doing my own car a week ago, I didn't know how timely it would be. Last week here in New Jersey ambient temps were in the mid to high 100's. My car ran great in the heat, well below 200 on the highway and maxed out at 214 stuck in stopped traffic, with 109 on the dash temp display. This weekend I intend to change the coolant just because it's timely maintenance. Also, since your heating problem seemed intermittent, for the price I would definetely changed the thermostat. If you have access to get your fan turn-on temps changed, I would consider getting a lower temp thermostat. It can help your car run lower temps.

 

Could it be a sticking tstat?
Things to consider:
Flush radiator and replace with 50/50 distilled water and DexCool.
Check or change hoses.
Replace the thermostat.
Replace the radiator cap.
Clean any crap between the radiator and the A/C.
All of the above is not expensive and not to difficult to do.

 

 

preciate all the advice

 

Sounds like either.

1) Thermostat stuck closed.
2) Fans not turning on.

 

when u turn the a/c on make sure both fans are turning on if not u will have a big problem o and make sure to check under the bottom of the radiator for blockage usually leaves or bags get stuck in this area and clean it good theis is where your car gets its all its air by the front spoiler pushing air up into this area

 

Also you could have a lot of debris in the a/c condensor and radiator fins. Especially if they have not been cleaned since the car was new. Last car I cleaned was running 230-245 and had enough fur etc in there to make two cats. Now it runs 180-190 all day long.

 

I have a 98 c5 corvette i just put a new thomo and a new rad on it and it will stay at 210-220 fine just sitting in idle but if i take the rpm's up to 3k for a second it will start to rise in temps then if i drive it it will start to rise to 230 then 240 then so on til i cut it off. I had a tranmissions line leaking some of the trans oil got on the belt i dont know if the belt is slipping or what but i really need help i tryed to burb the system still getting the same thing. i can leave it sitting in the driveway for a hour with no overheating but soon as i start driving it starts to rise water pump has no leaks i have no leaks from the cooling system and i have no signs of head gaskets gone bad someone plz hlep me its finna be spring and i just wanna enjoy the season

 

Qcityhgi444,

Don't take this the wrong way but thermostat could be upside down. Easy way to tell if you don't want to pull the housing is to check and see if the hose's are getting hot at temp.

 

It's always better to start a new thread.
Based on previous answers, it's usually either air in the system or a clogged radiator (bottom feeders). Amazing the type of junk that can accumulate in those fins. If you clean the radiator, remember to clean the udders also.

 

The thermostat is one with the housing when I got it from autozone the radiator is new the thermo is new I cleaned my AC condenser with a pressure hose it's clean clean of debris and I can feel the air flow thru it from both my fans being on the car will sit in idle with no problem I let it sit for 2 hours it stayed at 205 and 210 but soon as I start to drive it will go up to 230 then 240 and then when I stop shut the engine off and twist the radiator cap to release some pressure it goes rite back to 220 then drops to 210 I just ordered a new water pump hoping this will fix it I have burb the car over and over but when I start to drive it the temps go right back up the water pump is 3 years old it is not leaking any but I do smell a funny burn smell in the car after it's been running for a min I know it can't be a bad head gasket becuz it will sit in idle for hours without running hot it's no way to put the thermostat in backwards it came with the housing as one has anyone else had this problem before

 

MIght want to check the fan relays. My guess (based on my own experience) is that only one of your fans are turning on. There are 3 relays that control the fans. Sorry I don't recall the numbers. One of mine was bad, replaced it, both fans now run, problem solved.

 

the first thing you should do is make sure the condenser and radiator fins are clean. The only way to clean it real good is take the radiator out and flush the fins with water, then do the condenser in the car and do both backward of air flow.