Engine overheating

Tiny
SONNY TATE
  • MEMBER
  • 1995 CHEVROLET CORVETTE
  • V8
  • 2WD
  • AUTOMATIC
  • 43,000 MILES
When running at highway speed (sixty to seventy mph) temperature gauge shows about 200 to 205. When you stop and idle for just a short time, the gauge goes up to 260 or above. When you get back to highway speed, temperature goes back to approximately 200. I have replaced the temperature sensor but this did not help.
Sunday, August 12th, 2018 AT 2:18 PM

11 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Good afternoon.

Possible Causes:

1. Radiator clogged with debris from the road causing a restriction. Clean it with a high-pressure wash at a self-serve car wash.

2. Cooling fan not working. Make sure the cooling fan is functioning at idle pulling in cool air from the front of the car.

3. Shroud. You have a shroud around the front by the radiator. Make sure it is there and completely intact.

Roy

https://www.2carpros.com/articles/engine-overheating-or-running-hot

https://www.2carpros.com/articles/how-a-clutch-fan-works

https://www.2carpros.com/articles/how-an-electric-cooling-fan-works

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Sunday, August 12th, 2018 AT 3:38 PM
Tiny
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  • 5 POSTS
I will try your suggestions and let you know if they worked. Thanks for your help.
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Monday, August 13th, 2018 AT 12:41 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Sounds like a plan.

Roy
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Monday, August 13th, 2018 AT 12:49 PM
Tiny
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  • MEMBER
  • 5 POSTS
Did everything you suggested. Also checked engine, hoses, radiator, water pump, and all parts of engine with digital thermometer and all checked places showed normal or below 200. Car still shows 200 to 210 at highway speed and goes to 250 plus when idling. All fans working properly. Could the gauge be faulty?
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Wednesday, August 15th, 2018 AT 8:29 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Take the temp of the radiator at the top and then at the bottom and tell me what they are.

Did you change the thermostat?

Roy
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Wednesday, August 15th, 2018 AT 8:42 AM
Tiny
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  • MEMBER
  • 5 POSTS
Top reading is 178 and bottom is 185. Reading om water pump is 210. I have not changed our the thermos.
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Wednesday, August 15th, 2018 AT 10:37 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
The temperature at the bottom should be colder than the top.

From those readings, it looks like the radiator is clogged.

Roy
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Wednesday, August 15th, 2018 AT 10:41 AM
Tiny
SONNY TATE
  • MEMBER
  • 5 POSTS
Thank you for your information and answer. Certainly, I trust your opinion, but would ask this. I have taken the car to two old Corvette owners who work on and build cars, and one mechanic and they seem to think that the gauge on the car dash is defective and not reading the correct temperature. Is there a reason you think otherwise?
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Wednesday, August 15th, 2018 AT 11:14 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Yes, based on your temperature reading of the top and bottom of the radiator.

The bottom should drop 40% from the top temperature.

Roy
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Wednesday, August 15th, 2018 AT 12:20 PM
Tiny
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  • 5 POSTS
Does this mean that if the top temperature is 179 that the bottom temperature should be 136? Also, if radiator is clogged, should I go ahead and install a new radiator?
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Wednesday, August 15th, 2018 AT 5:14 PM
Tiny
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  • MECHANIC
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That would be correct.

Replacing it would be the best choice.

Roy
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Wednesday, August 15th, 2018 AT 11:53 PM

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