low coolant warning light.
Thread Starter
6th Gear
Joined: Oct 2010
Posts: 6
Likes: 0
From: Melbourne Florida
low coolant warning light.
On my 1988 vette, I have a issue with the low coolant light coming on at times when the temp is fine 194 - 204. The coolant levels are full, water pump is new, car runs great. It seems like a vapor lock but I just can't get rid of it. Has anyone had this issue or any ideas on how to fix it?
Thank you
Thank you
Thread Starter
6th Gear
Joined: Oct 2010
Posts: 6
Likes: 0
From: Melbourne Florida
I have not checked it when it is cold out of the tank but, It does not come on until the car gets to about 204 - 206, then comes back down to 194. The car needs to be running for about 15 minutes before this starts.
Thanks for the help
Thanks for the help
Race Director
Joined: Jul 2003
Posts: 12,742
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From: Color my life with the chaos of trouble.
I've had a cover over the coolant warning light in my 1987 for about 9 years because no matter what I did it would stay on... 
How often do you actually lose coolant without something being obviously wrong?
But yes... it sounds like a bad sensor to me. They can get gunked up over time.
How often do you actually lose coolant without something being obviously wrong?
But yes... it sounds like a bad sensor to me. They can get gunked up over time.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Could be that as the sensor is getting warm, the readings change. Either way, get readings cold and get readings warm. See what the sensor is seeing.
Team Owner
Joined: Jul 2004
Posts: 28,475
Likes: 3,291
From: Hartford WI
Not sure. You don't have a valve there. In my 91, the radiator feeds to a tank and there is an overflow tank it hooks to. The tank is the highest spot so driving will burp it.
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Safety Car
Joined: Jan 2004
Posts: 3,759
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You get the engine temp to 200* or so with the radiator cap off. As you want the thermostat opened. Then you open the throttle at the engine and stick a nickle under the screw to keep the throttle opened up. You will see the coolant goes down in the radiator. You fill the radiator up with more coolant. Put the radiator cap on. Then remove the nickle.
Burning Brakes
Joined: May 2010
Posts: 941
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I was just going to post that the system probably needs burping. With the system cold, T Stat closed you have what appears to be a normal level. The the T stat opens and coolant circulates and the level in the radiator goes down.Heres how I burp my 87.
First, Engine must be cold so you dont get burned.
I jack up the front right corner so the tire is about 4 inches off the ground. Then remove the radiator cap and start the engine. When the engine gets up to temperature and the T Stat opens ( you will see water flowing in the radiator and the top hose will get hot). Open the throttle so the engine is running about 1500 R's or so. You will see the water level go down. HOLD the throttle open at the 1500R's and fill the radiator to the top, put the cap on and tighten. Then and only then do you release the throttle back to idle. Now your burped and there should be no more air in the cooling system. It should be solid coolant. Lower the can to the ground and your done.
8Valve
Le Mans Master
Joined: Dec 2004
Posts: 5,789
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From: Myrtle Beach SC
St. Jude Donor '05-'06
Is this "low coolant" or "low coolant temp"? If it is temp then Burping it wouldn't do a thing it is a sensor issue and it may be bad. The low coolant switch in the reservoir has nothing to do with air in the system unless the coolant dissapears totally.In the FSM there is a guide to check the sensor but it is a varistor that changes with temp and a VOM can check it. I do not recall what the Ohms should be try a search
Last edited by Redeasysport; Oct 11, 2010 at 03:15 PM.
Safety Car
Joined: Jan 2004
Posts: 3,759
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When I had changed my hoses and flushed the coolant and forgot to do the final burping. I got the occasional low coolant level light. I burped it and the light has never come back on. Some guys have had to burp 2 or 3 times.
Safety Car
Joined: Nov 2004
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From: going faster miles an hour...with the radio on in browns mills new jersey
Even with a normal coolant level, I can get the low coolant level light to come on while driving twisty roads in a spirited manner.
After a while the light will go out. If I drive 'normally', the light won't come on.
Jensen Button! Jensen Button!
After a while the light will go out. If I drive 'normally', the light won't come on.
Jensen Button! Jensen Button!
Team Owner
Joined: Jul 2004
Posts: 28,475
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From: Hartford WI
