Could my headders be the reason my vette is overheating? o_O

[Nick90vetteguy]

SO my vette is overheating agian, could it be because my ceramic headders give off more heat than stock? did a coolant flush, fans turn on, could it be my gauge be wrong?

 

[G Winter]

Maybe a lean condition ?


Glenn

 

[Nick90vetteguy]

hmm...lean as in a bad injector?

 

[gmjunkie]

SO my vette is overheating agian, could it be because my ceramic headders give off more heat than stock? did a coolant flush, fans turn on, could it be my gauge be wrong?

How Hot is Hot?~??:confused

 

[Nick90vetteguy]

Hi jmjunkie, its anywhere from 250 to 260 :ugh I had the vetet for about a year now, since i put headders on it and a 58mm throttle body(im taking it off soon and putting back the 52mm soon) it started over heating, I changed the fuse a while back, had the coolant flushed, installed a Mr. Gasket 160 degree thermostat, ya know the more I think about it, the coolant that is in my vette now isnt GM (orange) coolant, I don't know if that plays a role, but when I'm at a light thats when it starts to rise, when im crusing, it goes down little by little

 

[muddywaters]

I know that this has been beat to death but, Did you check in between Radiator and condensor?? My 88 was squeaky clean when I bought it, I felt that the cooling wasn't right, I was horrified to find that area loaded with leaves, lottery tickets, cig. wrappers, etc. It looked like a vacumn cleaner bag. Just a thought.

 

[Nick90vetteguy]

Yea i heard about the "street-sweeper" effect that these vettes have but no i havent checked it yet

 

[Hib Halverson]

1) 250-260 is in the danger zone. If you are seeing those ECTs regularly and have been seeing them for a while, engine damage is possible. I'd stop driving the car and start some cooling system diagnosis.

2) The problem is not your ceramic-coated headers. They will reduce heat radiated from the exhaust but will not affect ECT enough to put it to 250-260.

3) For the engine to run that hot because of lean AFR, it would have to be really, really lean and that would turn on the check engine light and set a code for lean exhaust.

Has the light been on? If so, what code(s) were set?

4) Whether the coolant is "traditional" antifreeze or Dexcool is not an issue, here. Also, Dexcool was not used in a 90.

With respect to the very high ECT, first I'd remove the top of the cooling stack and inspect the area ahead of the radiator and the space between the hvac condenser and the radiator for debris. If you see any, remove it.

Next, I'd verify the cooling fan(s) work using the information in the Factory Service Manual.

After that, I've make sure your aftermarket thermostat is not faulty

Check to make sure the radiator is not restricted.

Let us know what you find.

 

[Nick90vetteguy]

1) 250-260 is in the danger zone. If you are seeing those ECTs regularly and have been seeing them for a while, engine damage is possible. I'd stop driving the car and start some cooling system diagnosis.

2) The problem is not your ceramic-coated headers. They will reduce heat radiated from the exhaust but will not affect ECT enough to put it to 250-260.

3) For the engine to run that hot because of lean AFR, it would have to be really, really lean and that would turn on the check engine light and set a code for lean exhaust.

Has the light been on? If so, what code(s) were set?

4) Whether the coolant is "traditional" antifreeze or Dexcool is not an issue, here. Also, Dexcool was not used in a 90.

With respect to the very high ECT, first I'd remove the top of the cooling stack and inspect the area ahead of the radiator and the space between the hvac condenser and the radiator for debris. If you see any, remove it.

Next, I'd verify the cooling fan(s) work using the information in the Factory Service Manual.

After that, I've make sure your aftermarket thermostat is not faulty

Check to make sure the radiator is not restricted.

Let us know what you find.

Dexacool thats what i meant thanks haha, ok well no codes have came up, SES light hasnt been on at all this year, nothing comes up when I poke it with the paperclip, where should I look to find any debris between the fans and radiator?

 

[Hib Halverson]

Dexacool thats what i meant thanks haha, ok well no codes have came up, SES light hasnt been on at all this year, nothing comes up when I poke it with the paperclip, where should I look to find any debris between the fans and radiator?

Read the FSM under cooling to learn how to disassemble the top of the cooling stack. Once you do that you'll be able to see the spaces in front of the radiator, between the hvac and the radiator and behind the radiator. Remove any debris you find.

Then try the other suggestions in my earlier post to this thread.

Good luck.

 

[93Rubie]

I am assuming the coolant is full and you do not have any air pockets? (system was bleed properly)

 

[Nick90vetteguy]

hmm I dont know if there are any airpockets how can I bleed it? is it that apark on a hill trick?

 

[TedC]

This is the process I use with great success for burping air out of an L98...

Run the engine with the radiator cap off. When the thermostat starts to open, you will see coolant flow inside the radiator. I add coolant as required, some coolant will burp out (especially as it warms up and if there are any air pockets). Increase and hold the engine RPM around 1200 RPM which causes the coolant level to drop about an inch. Quickly top off the coolant level and install the radiator cap completely.

As already stated, clean out the "vacuum cleaner bag". The crap that build up and how high it builds up is truely amazing. I found 4" of stuff on my 1989, including newspaper print that was dated in the 1990s which tells me it was never cleaned out.

 

[Nick90vetteguy]

anytime i flush out my coolant, is this something that HAS to be done, or is this something that occurs when its not properly filled( ie: opening the radiator cap n burping it)

 

[TedC]

Yes. L98 really likes to trap air after any type of coolant maintenance that requires you to drop coolant levels. Procedure provided is very similar to the FSM. I improved my success rate to 100% by reving the engine and holding it just enough that lowers coolant levels an inch or so, then topping it off quickly and install the cap. Until the next coolant maintenance, I never need to remove the radiator cap. I monitor levels in the overflow tank.

 

[Jeb]

Yes. L98 really likes to trap air after any type of coolant maintenance that requires you to drop coolant levels. Procedure provided is very similar to the FSM. I improved my success rate to 100% by reving the engine and holding it just enough that lowers coolant levels an inch or so, then topping it off quickly and install the cap. Until the next coolant maintenance, I never need to remove the radiator cap. I monitor levels in the overflow tank.

I'm trying to be cute but are you sure the thermostat wasn't put in backasswards? I don't even know if it's possible but I do know it's been done before on other engines.

 

[jpushard]

overheating

I drilled a 1/8 hole in my thermostat and that seemed to help with the air pocket.
Good Luck