Strange engine temp issue
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 32
Likes: 0
From: Ft. Lauderdale FL
Strange engine temp issue
Yesterday, took the vette out for a spin. It's the first time it's been somewhat warm here, around 80 deg. The engine temp gauge was reading about 200 and a tick more. When I got home, I let it run at idle for a while till it got over the 200-210 mark +/-. Here's the strange part...just for grins, I turned on the A/C.... the temp started to DROP!! I've never seen this in any car. It would go back down to below 200.
Does anyone have a clue?? I've not driven the car for very long due to extensive repairs and paint work. This was really the first time driven in normal temps for South Florida.
Also, I have a front tag that is not needed by law, just decorative, should I remove it for more airflow to the radiator??
Thanks for any help.
Does anyone have a clue?? I've not driven the car for very long due to extensive repairs and paint work. This was really the first time driven in normal temps for South Florida.
Also, I have a front tag that is not needed by law, just decorative, should I remove it for more airflow to the radiator??
Thanks for any help.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
What year ? If it has an electric fan it can be set up to come on when the AC is turned on.
You could have a vacuum switch advancing your timing when the AC is turned on.
Your water shutoff valve could be hooked up wrong and allowing coolant to flow when the AC is turned on.
If the idle speed solenoid kicks up it can lower the temp.
Just a couple thoughts.
You could have a vacuum switch advancing your timing when the AC is turned on.
Your water shutoff valve could be hooked up wrong and allowing coolant to flow when the AC is turned on.
If the idle speed solenoid kicks up it can lower the temp.
Just a couple thoughts.
Last edited by ...Roger...; Feb 20, 2011 at 04:33 PM.
Melting Slicks
Joined: Aug 2005
Posts: 2,359
Likes: 15
From: Confusion
If car has been sitting a while, it is an air pocket in the coolant system. My 75 would do that after it sat all winter, the first time I would get it out for the "year" it would overheat several times while driving but after about 10 miles it would settle down.
Melting Slicks
Joined: Mar 2008
Posts: 2,023
Likes: 6
From: Austin Tx
What year ? If it has an electric fan it can be set up to come on when the AC is turned on.
You could have a vacuum switch advancing your timing when the AC is turned on.
Your water shutoff valve could be hooked up wrong and allowing coolant to flow when the AC is turned on.If the idle speed solenoid kicks up it can lower the temp.
Just a couple thoughts.
You could have a vacuum switch advancing your timing when the AC is turned on.
Your water shutoff valve could be hooked up wrong and allowing coolant to flow when the AC is turned on.If the idle speed solenoid kicks up it can lower the temp.
Just a couple thoughts.
To the OP - is there a hot water shutoff valuve? How well does the heater work?
Thread Starter
Intermediate
Joined: Dec 2005
Posts: 32
Likes: 0
From: Ft. Lauderdale FL
The car does not have a shut off valve...as far as I can tell, the heater does not work. I did have the spike in temp while driving that might have been the air pocket a previous poster mentioned. It jumped up about 1/4 higher than the temp and then just as suddenly lowered to the normal temp.
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Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Check your thermostat...I'd start vette cold,then watch temp gauge as engine warms up,..temp should peak,then drop as thermostat opens.
Another possibility is lower tube clogging in your radiator...but that is hard to detect...but a good flush may show something..
Another possibility is lower tube clogging in your radiator...but that is hard to detect...but a good flush may show something..
Drifting
Joined: Jun 2006
Posts: 1,912
Likes: 12
From: Schaumburg (Chicago) Illinois
I don't know much about this stuff but I had a over heating engine when the body was off. Folks here had a lot of suggestions but I couldn't solve the problem. The kid working at the auto parts store said the system needed to be pressurized to work it's best. I figured what does he know, he was just a kid, but I figured I would try. My system was open because I hadn't yet hooked up the coolant reservoir with the cap. The very first time I started the car after I attached the reservoir and cap it ran right where it should be and was about 30 degrees cooler (If memory serves). So, maybe your system is not pressurizing due to a faulty cap?