2000 Corvette overheating issues
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Instructor
Joined: Jul 2018
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2000 Corvette overheating issues
Last fall I was driving my 2000 C5 and out of the blue the engine overheating light came on. I limped the car a few blocks to my house and popped the hood. The overflow tank had sprung a leak and was spitting up coolant in a mist. I thought that's an easy fix so I ordered a new overflow tank and installed it. That didn't fix the problem as the car was still overheating to the point where the temperature gauge would peg all the way in the red if I kept the car running long enough. Fans were kicking on BTW. I decided to winterize the car and over the winter I ordered a new water pump, new thermostat and a new thermostat housing. Last weekend was so nice that I took the car out of the garage and installed the new parts. I filled with the dex cool coolant and burped the system so I know there was no air in the lines. Still overheating.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
Tech Contributor
Joined: Jan 2007
Posts: 19,398
Likes: 1,139
From: Dyer, IN
Last fall I was driving my 2000 C5 and out of the blue the engine overheating light came on. I limped the car a few blocks to my house and popped the hood. The overflow tank had sprung a leak and was spitting up coolant in a mist. I thought that's an easy fix so I ordered a new overflow tank and installed it. That didn't fix the problem as the car was still overheating to the point where the temperature gauge would peg all the way in the red if I kept the car running long enough. Fans were kicking on BTW. I decided to winterize the car and over the winter I ordered a new water pump, new thermostat and a new thermostat housing. Last weekend was so nice that I took the car out of the garage and installed the new parts. I filled with the dex cool coolant and burped the system so I know there was no air in the lines. Still overheating.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
Last edited by lucky131969; Apr 16, 2024 at 08:19 AM.
Safety Car
Joined: Mar 2017
Posts: 3,767
Likes: 938
From: Orlando Florida
You have not installed a splitter, and the air dam is intact, yes?
Many reports of bags and other debris coming up from under the nose and blocking the radiator — you’ll eliminate that possibility with the new unit, of course.
I’d also suggest that checking for good head gaskets would be a worthwhile endeavor. Combustion leak detectors are $30 (plus fluid) at both Autozone and Harbor Freight.
Many reports of bags and other debris coming up from under the nose and blocking the radiator — you’ll eliminate that possibility with the new unit, of course.
I’d also suggest that checking for good head gaskets would be a worthwhile endeavor. Combustion leak detectors are $30 (plus fluid) at both Autozone and Harbor Freight.
Racer
Joined: Mar 2018
Posts: 456
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From: Frederick Colorado
Persistent overheating issues are a “worst-case scenario,” and I see a head gasket in your future.
Possibly a new engine. Once coolant gets into the oil… and you’ve pegged the thermostat, the cancer has metastasized, so to speak.
Possibly a new engine. Once coolant gets into the oil… and you’ve pegged the thermostat, the cancer has metastasized, so to speak.
Racer
Joined: Mar 2018
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From: Frederick Colorado
Pro
Joined: Aug 2010
Posts: 622
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From: Montgomery Texas
Aluminum engines DO NOT like to be overheated ... even a little bit. "Limping" a couple of feet, is enough to seal the deal, much less blocks. When overheating, you must shut them down immediately, without hesitation and even that may not be soon enough.
Sure, hope for the best, but assume the worst. Either way, it's time to look for steam-cleaned spark plugs, coolant ingress into the cylinders and compression & leak-down tests.
Best of luck!
Sure, hope for the best, but assume the worst. Either way, it's time to look for steam-cleaned spark plugs, coolant ingress into the cylinders and compression & leak-down tests.
Best of luck!
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Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
Racer
Joined: Mar 2018
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From: Frederick Colorado
Last edited by FOGeologist; Apr 17, 2024 at 02:38 PM.
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
I can certainly understand the trepidation for anyone not having a full understanding of the validation testing required to actually put that into print. A lot has changed in 50 years with the advent of electronic fuel injection.
Pro
Joined: Oct 2006
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I have had the following overheating problems:
Failed fan motor several times--most noticeable at low speeds or stop and go traffic
Dirty radiator--cleaned
Long uphill, 120+ deg day in Death Valley--Probably at design limit, near redline but didn't go over
Failed fan motor several times--most noticeable at low speeds or stop and go traffic
Dirty radiator--cleaned
Long uphill, 120+ deg day in Death Valley--Probably at design limit, near redline but didn't go over
Pro
Joined: Aug 2010
Posts: 622
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From: Montgomery Texas
Aluminum engines DO NOT like to be overheated, period ... regardless of what GM's legal team may print in your owner's manual.
Tech Contributor
Joined: Jan 2007
Posts: 19,398
Likes: 1,139
From: Dyer, IN
GM has to worry about the liability of telling folks to immediately stop in the middle of traffic. Of course they are not going to advise you to immediately pull over. Instead, they advise you to look for a safe place to pull over. Notice what they do not say in that paragraph. They don't guarantee that there will not be any damage to your engine. They merely say that their limp strategy will help to minimize damage. Of course, due to this advise, they will have great difficulty in refusing a warranty repair, but what happens after the warranty expires? The answer is that it's no longer GM's problem when you cook your engine.
Aluminum engines DO NOT like to be overheated, period ... regardless of what GM's legal team may print in your owner's manual.
Aluminum engines DO NOT like to be overheated, period ... regardless of what GM's legal team may print in your owner's manual.
Thread Starter
Instructor
Joined: Jul 2018
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Last fall I was driving my 2000 C5 and out of the blue the engine overheating light came on. I limped the car a few blocks to my house and popped the hood. The overflow tank had sprung a leak and was spitting up coolant in a mist. I thought that's an easy fix so I ordered a new overflow tank and installed it. That didn't fix the problem as the car was still overheating to the point where the temperature gauge would peg all the way in the red if I kept the car running long enough. Fans were kicking on BTW. I decided to winterize the car and over the winter I ordered a new water pump, new thermostat and a new thermostat housing. Last weekend was so nice that I took the car out of the garage and installed the new parts. I filled with the dex cool coolant and burped the system so I know there was no air in the lines. Still overheating.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
I ordered a new radiator and it arrived yesterday. I'm hoping this fixes the issue because I'm at a loss if this doesn't work. If anyone had a similar experience then let me know what fixed it for you.
I'll update after I install the new radiator which I hope to get done tomorrow or Wednesday.
So I removed the cap, inserted the tube till it was snug and started the car. Once the car ran a few minutes I added the tester fluid and started the test. The fluid stayed blue. After about ten minutes the car never overheated. It was staying steady at 200 or so. Kept squeezing the ball but it stayed blue.
So far so good. I switched from heat blasting to air conditioning because I wanted to see if the fans would kick on high and stay on. About two minutes later all hell broke loose. The coolant level rose fast and started overflowed out of the reservoir fast. I removed the tube just as this was starting to happen and shut the car off.
Fluid was still blue and the temp gauge showed 225!which was just a hair past the center.
Not sure what this means. Any insight?
I have not yet installed the new radiator because of the fluid turned yellow then there was no need to do that until I ordered and received new head gaskets.
Pro
Joined: Dec 2014
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From: Cincinnati Ohio
I am not clear what this tube you are describing is or does. Was the cooling system pressurized during your test? Did you have the radiator cap off when it was boiling over? If so, a 50/50 mix of coolant will boil at 223 degrees F. A lower concentration of coolant will boil at a lower temperature.
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Instructor
Joined: Jul 2018
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I am not clear what this tube you are describing is or does. Was the cooling system pressurized during your test? Did you have the radiator cap off when it was boiling over? If so, a 50/50 mix of coolant will boil at 223 degrees F. A lower concentration of coolant will boil at a lower temperature.
Since the liquid stayed blue thats supposed to indicate that I don't have a leaking head gasket. I suppose the next step is to replace my radiator, fill, burp, top off and pray.
Tech Contributor
Joined: Jan 2007
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From: Dyer, IN
The coolant level rose fast and started overflowed out of the reservoir fast. I removed the tube just as this was starting to happen and shut the car off.
Fluid was still blue and the temp gauge showed 225!which was just a hair past the center.
Not sure what this means. Any insight?
Fluid was still blue and the temp gauge showed 225!which was just a hair past the center.
Not sure what this means. Any insight?
Pro
Joined: Dec 2014
Posts: 682
Likes: 276
From: Cincinnati Ohio
It is a pretty good guess then that all hell broke loose when your coolant temperature approached 223 degrees, assuming you have 50/50 coolant. Wherever that temperature occurred within the engine coolant passages, the coolant began to boil.
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Instructor
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Yeah, it's a pressurized system. Once the thermostat opens and circulation starts, you only have so much time before it will overheat if the system is open. You can't just leave the pressure cap off the resevior, or that's what happens. You hastened the process by turning the AC on. No offense intended, but you should really just take the car to a trusted shop.
You actually want to hasten the process in order to make sure that your fans kick on properly and so the test will be accurate and that is per the instructions and a few youtube videos I watched ahead of time. It just took me by surprise because the temp held steady at 200 for several minutes. Then when the needle moved it really moved fast. The good news is that the test fluid stayed blue so I don't think I have any issues with my heads, block or gaskets. I lost a little anti-freeze but gained some piece of mind.
Taking the car to a shop is a last resort for me. I've installed headers, cams, starters, alternators, water pumps, brakes, ball joints, control arms, harmonic balancers and that's just to name a few. I've saved thousands in labor fees over the years and every project has ended with success. I just need to figure out why its overheating and so far I have eliminated water pump, thermostat, hoses and head gaskets.