hello I am a new member and I am very pleased that I registerd with such a great forum ,I had learned allot from the recent topics ,I have an 88 red on red with 36k miles and my brother has an 89 with only 5k miles red on black, but I have a question about my 88 when I turn the a/c the coolant temp on the dash will go up to 160*c / 290*F it stays a little and then go to normal Lo temp than it will go back to hi temp , the corvette is not overheating becouse even when I start it ,it does the same ,what do you think :confused: any replys will be greatly appreciated Thank - you :flag

 

First of all welcome to the board! There are some really knowledgeable people here. :) Red on Red is the best!

Second, to me it sounds like your coolant temperature sender is faulty. To be safe I would get a new thermostat and coolant temperature sender. May cost you $40 total. Cheap easy fix.

Good luck! :)

:D

 

Welcome..........we love '88's here!!! :lol: :lol: :yesnod: :yesnod:
:seeya

 

Welcome to the forum!

Have you checked for air in your coolant system?

:cheers:

 

Welcome to the Forum.

First off, 290deg F is way too hot even for a stock Vette. Yes, first off check/replace the thermostat. With a temp reading that high I too would suspect the temp sender as being faulty.

 

:seeya Welcome!! :cheers:

 

temperature sender is bad, then check your temps :seeya :seeya :seeya


[Modified by vader86, 11:23 AM 7/18/2002]

 

:seeya Welcome!!

 

Welcome to your new addiction. There are some very helpful people in the forum. :yesnod: :yesnod:

 

Welcome to the forum :seeya The people here are the greatest :cheers:

 

Thank you all for the replys I realy appreiciated I am very pleased that I am with such corvette fans :chevy my corvette looks the same as -fixvet- corvette I think that thay are twins :D ,when I turn the A/C OFF the problem will go away the thing is realeted to the A/C ,with the A/C off the coolant temp will be the same like the oil temp ( a bit lower ) but when I turn the A/C on it happens the coolant temp will go up to the limit ,but the engine is runnung fine :confused: again THANK YOU all I love you all :flag

 

Welcome to the forum!!

 

Marlon88,

I agree with Kenfusion...I think you need to burp your radiator.

290*F is way out of line. The fact that you are not over-heating, causing you to lose no coolant, tells me you must have air in the cooling system, which in turn is giving you such a high temperature reading.

First thing I would do is get a piece of paper...take your car for a 15 minute run, and note what the highest temperature reading is displayed.

Return home, and after a cooling down period............

Try this: Start your engine, and let run for 10 minutes. Shut off the engine, and let cool for about five minutes.

Restart the engine, and remove the radiator cap very carefully, and very slowly. (Protect yourself with a towel, so as not to get any hot water burns).

After a minute run, increase the RPM's to 2500 RPM's. You should notice the radiator requires more coolant, if in fact there is air in the coolant system.

Quickly, after you've added additional coolant, lock down the radiator cap.

Keep engine running another 5 minutes.

Take a look at your temp gauge. Are the numbers reading any better? Record your readings, and take another 15 minute run.

Record your readings...whatever the highest reading is.

You may have to repeat this a couple of times in order to get all the 'air' that is in your system...out.

As a footnote: You will not get the same results by adding coolant to your overflow tank. You'll still have air in the system.

Good Luck!!

John




[Modified by UDLUV12, 1:31 PM 7/18/2002]

 

Welcome to the Forum and congrats on your new Vette!

 

Welcome to the forum!! :yesnod:

After reading your post, and some thought, I'm not so sure it's air in the cooling system. If I understand right, you said the temp reading went up right after you switch on the A/C... even when you first start the car. Air can cause overheating but it's not likely that it would only happen when you turn on the A/C and certainly not if the engine is cold at startup. As for the temp sensor, it can fail and give false readings but it's not likely that it fails only when you turn on the A/C. The temp sensor is a thermistor, varying it's resistance when the temp changes, and it's resistance is converted to a digital value by the ECM. When you turn on the A/C the ECM has more work to do... more inputs to monitor. I'd be suspicious of a bad ECM or a connection going to the ECM. Another thought is the temp sensor is mounted to the front of the intake manifold under the air control valve assembly (part of the air pump system). Maybe the wire is chaffed and shorting out, or the connector is loose and wiggling, when the A/C cycles on and off adding vibration to the engine. That's my 2 cents worth. ;)

Good luck! Let us know what you find.

:flag

 

I'll be watching this thread. I have that problem too, although temps dont get that high :eek:, when my A/C is on.

 

Welcome :seeya

 

Welcome :cheers: :seeya

 

Thank you all for the replys ,Today I went to check again with the A/C on and it still does the same ,the temp will go up as the fan started ,then I took a look at the temp sensor the one located near the engine dip stick and it has 2 wires one green and one black while my brothers 89 has only one green wire :confused: , then I took off the green wire from the sensor on mine and the coolant temp stays Lo all the time even with the A/C on :confused: so I think it somthing with the sensor or ???what you think ,the owner before me claims that the problem was there even when he bought it 5 years ago :mad please help !! all of you had been very friendly :cheers: I am proud that I own a vette :chevy

 

Welcome :seeya