heating up stop & go
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
heating up stop & go
So im sure this isnt a new problem my cars overheating now, on the freeway iam getting right behind 220 with a/c on or off. When iam in stop and go traffic not even for long i get to 230 and slowly to 240 max if i dont move. If iam parked idle i pass 220 in like 2mins if i rev at 2k for a little i climb towards the 230 -240(a/c on or off) also but i let off by then and turn the car off. I changed the hoses today and going to fill up any missing fluids from what was dropped today if any later on when it cools down. Not sure whats wrong iam going to change thermostat next . Any suggestions my fellow Corvette Brothers/sisters 
(i have checked other threads seen pump could be it but i cant pay for that today i got a cat i need installed this monday)
(i have checked other threads seen pump could be it but i cant pay for that today i got a cat i need installed this monday)
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
1 Make sure the font of the radiator is not clogged up full of debris like weeds etc
2 Make sure the fans are coming on # 1 comes on at 226* # 2 on at 235*
3 Install a 160 thermostat
4 Have a mail order tuner reset your fan on/off temps #1 On at 200 OFF at 195--#2 On at 205 OFF at 201
5 make sure you "burp" the air out of your cooling system--(let the car warm up without the cap on -once the thermo opens it should burp out all of the air) refill radiator Air in your cooling system will make it overheat---
2 Make sure the fans are coming on # 1 comes on at 226* # 2 on at 235*
3 Install a 160 thermostat
4 Have a mail order tuner reset your fan on/off temps #1 On at 200 OFF at 195--#2 On at 205 OFF at 201
5 make sure you "burp" the air out of your cooling system--(let the car warm up without the cap on -once the thermo opens it should burp out all of the air) refill radiator Air in your cooling system will make it overheat---
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
1 Make sure the font of the radiator is not clogged up full of debris like weeds etc
2 Make sure the fans are coming on # 1 comes on at 226* # 2 on at 235*
3 Install a 160 thermostat
4 Have a mail order tuner reset your fan on/off temps #1 On at 200 OFF at 195--#2 On at 205 OFF at 201
5 make sure you "burp" the air out of your cooling system--(let the car warm up without the cap on -once the thermo opens it should burp out all of the air) refill radiator Air in your cooling system will make it overheat---
2 Make sure the fans are coming on # 1 comes on at 226* # 2 on at 235*
3 Install a 160 thermostat
4 Have a mail order tuner reset your fan on/off temps #1 On at 200 OFF at 195--#2 On at 205 OFF at 201
5 make sure you "burp" the air out of your cooling system--(let the car warm up without the cap on -once the thermo opens it should burp out all of the air) refill radiator Air in your cooling system will make it overheat---
Pro
Joined: Dec 2014
Posts: 682
Likes: 276
From: Cincinnati Ohio
I suspect others will disagree with me but 220 degrees just driving on the highway at 60, 70, 80 mph is high; even in Arizona at 100 degree ambient. If you are having temperature problems at highway speeds it’s not the fans because they should not need to turn on.
Are you basically stock? Highly modified?
First things first, when was the car running at what you considered to be normal and was anything done to the car since then?
When you noticed this hot behavior, was your coolant level normal? Have you noticed a loss of coolant? If no coolant loss than that eliminates a leak and probably eliminates a blown head gasket.
Air side - no plastic bags blocking the condenser or radiator?
Coolant side- sticky or stuck thermostat, maybe. Plugged radiator tubes was a problem in the old days but long life coolants, regular changes, and aluminum radiators make that rarer. Hopefully your car has had the coolant changed at recommended intervals and with comparable coolant. Water pump-I can’t speak about a C5 but typically a pump is just an impeller and a housing. As long as it isn’t seized and doesn’t leak, it just spins and pumps. If your pump was seizing I have to think you would hear or smell the belt.
Are you basically stock? Highly modified?
First things first, when was the car running at what you considered to be normal and was anything done to the car since then?
When you noticed this hot behavior, was your coolant level normal? Have you noticed a loss of coolant? If no coolant loss than that eliminates a leak and probably eliminates a blown head gasket.
Air side - no plastic bags blocking the condenser or radiator?
Coolant side- sticky or stuck thermostat, maybe. Plugged radiator tubes was a problem in the old days but long life coolants, regular changes, and aluminum radiators make that rarer. Hopefully your car has had the coolant changed at recommended intervals and with comparable coolant. Water pump-I can’t speak about a C5 but typically a pump is just an impeller and a housing. As long as it isn’t seized and doesn’t leak, it just spins and pumps. If your pump was seizing I have to think you would hear or smell the belt.
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
iam stock i shadow 220 on highway so right before getting to it my fans work they kick on and drop me back down at higher temps. My problem is in basic normal city traffic when i sit their waiting for the lights. My normal use to be 180 i would never pass that. i have only got new tires and changed my brakes so nothing really, no coolant loss or leaks. My radiator has very little leaves nothing that seems that serious or to cause blockage. I was planning to get a new thermostat tomorrow after work . i feel like the Rad might be clogged or something internally or pump but the pump seems fine slightly worn down on belt but nothing that seems like it would cause such an issue, pump doesnt leak. I might get a 180 thermostat not sure as long as i dont get check engine lights from the change. Temps have been at 115 also recently 100-115 in AZ
Last edited by Venom602; Aug 27, 2020 at 11:24 PM.
Pro
Joined: Oct 2006
Posts: 515
Likes: 133
Unlikely to be thermostat.
Fans should be both on low at 226, both on high at 235. Is this what they are doing?
Your temps are somewhat high for 115 OAT. but not extremely so.
besides leaves, just plain dirt can reduce radiator effectiveness, maybe need to clean.
I have seen this, once it was fan motor, second time combination of fan motor and dirty radiator
Fans should be both on low at 226, both on high at 235. Is this what they are doing?
Your temps are somewhat high for 115 OAT. but not extremely so.
besides leaves, just plain dirt can reduce radiator effectiveness, maybe need to clean.
I have seen this, once it was fan motor, second time combination of fan motor and dirty radiator
Drifting
Joined: Feb 2008
Posts: 1,596
Likes: 67
From: Bahama North Carolina
So im sure this isnt a new problem my cars overheating now, on the freeway iam getting right behind 220 with a/c on or off. When iam in stop and go traffic not even for long i get to 230 and slowly to 240 max if i dont move. If iam parked idle i pass 220 in like 2mins if i rev at 2k for a little i climb towards the 230 -240(a/c on or off) also but i let off by then and turn the car off. I changed the hoses today and going to fill up any missing fluids from what was dropped today if any later on when it cools down. Not sure whats wrong iam going to change thermostat next . Any suggestions my fellow Corvette Brothers/sisters (i have checked other threads seen pump could be it but i cant pay for that today i got a cat i need installed this monday)
(i have checked other threads seen pump could be it but i cant pay for that today i got a cat i need installed this monday)
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
my air dam is good still their and intact . Iguess i could try cleaning what it does have and see what happens with the thermostat today.
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Melting Slicks
Joined: Sep 2008
Posts: 3,132
Likes: 799
From: Espanola New Mexico
Sudden changes to operating temperatures and specifically during stop and go traffic sometimes means that one of your fans is not working, as mentioned in previous posts both fans should operate on low speed at the lower temp set point, and both fans should operate on high speed at the higher temp set point. If you are having higher then normal temps on the highway, then your radiator is probably plugged up with road debris, because fans are turned off once the car reaches 35mph.
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
is 225-230 bad/normal reving at 2k not moving just parked i changed the thermostat today 180 so same as i had. i only saw fan turn on when i got to 225. i cant see the drivers fan not sure how to verify if its working unless i jack it up im guessing its hard to see if its spinning it is 111 outside right now. i just fixed my damn gas gauge showing empty it happened today
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
since the thermostat replaced i hit 230 in stop and go traffic one time but it went back down to 220 in like 2mins. Fans will be first to change if not the Rad. could a wire/sensor be bad to the fans ? i still need to verify if the drivers side rad fan works
Safety Car
Joined: Mar 2015
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Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
so anything above 230 in stop and go traffic(or idle) would be considered a bad sign? i just never use to get this hot so im kinda on the sketchy feeling side right now i never use to hit 220
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
i will be doing that tomorrow after work this is my daily driver 
so im trying to keep it as best as i can without messing anything up. i will update tomorrow on fan status and temp changes, thanks for all the help so far 
so im trying to keep it as best as i can without messing anything up. i will update tomorrow on fan status and temp changes, thanks for all the help so far
Pro
Joined: Oct 2006
Posts: 515
Likes: 133
is 225-230 bad/normal reving at 2k not moving just parked i changed the thermostat today 180 so same as i had. i only saw fan turn on when i got to 225. i cant see the drivers fan not sure how to verify if its working unless i jack it up im guessing its hard to see if its spinning it is 111 outside right now. i just fixed my damn gas gauge showing empty it happened today
Safety Car
Joined: Mar 2015
Posts: 3,638
Likes: 245
i think jacking up the car might be easier
Thread Starter
Intermediate
Joined: Aug 2020
Posts: 27
Likes: 0
From: Arizona
some stuff was missing when i bought it like one of my valve covers was messed up but ive seen on the forums some temps regarding fan operations
Safety Car
Joined: Mar 2015
Posts: 3,638
Likes: 245
but in my not so professional opinion, that seems to be to normal operating temperature.