Low coolant light
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 780
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From: New Port Richey Florida
Low coolant light
Hey guys my low coolant light on the 86 is coming on and goes off no rhyme or reason, coolant level is full, no overheating it seems to be running fine. Any ideas. TIA Rich
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From: Bowling Green Kentucky
Racer
Joined: Sep 2007
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From: Bartonville Illinois
I have never looked on my car but I checked on on a Pontiac a while back for a relative. It was a float switch mounted high in the radiator. The switch was fine but was almost unplugged "electrically. If you can get to the switch you can move the mechanism and watch the dash for alarms and figure it out.
Racer
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From: Prescott Michigan
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Le Mans Master
Joined: Sep 2006
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From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
coolant light
the coolant light will come on and make that funny noise in the radio when the coolant is indeed low. The light comes and goes depending on how much gas you give the throttle if it is to actually come on..You will have to burp the radiator and determine that the overflow hose is in good shape with no cracks.
If that doesn't cure the problem, change your radiator cap.
The problem comes from improper filling of the radiator, or a bad hose, or a bad cap.The water pump compresses the air out of the system with pressure, and the radiator becomes the expansion space, and the sensor blade is above the water level. The car cools off after warming up, and the hose or cap is compromised, and the radiator cannot draw the water back into the radiator when the water contracts as it cools off.
Check the cap, the center metal part of the cap that touches the water is actually a small check valve that relieves under radiator vacuum. it opens, and the water is drawn back into the radiator. it should put the light out permanently if the radiator is serviced correctly.
The water touching the sensor provides a ground through the water and the frame to give the computer the ground it needs to complete the circuit that turns off the light.
If that doesn't cure the problem, change your radiator cap.
The problem comes from improper filling of the radiator, or a bad hose, or a bad cap.The water pump compresses the air out of the system with pressure, and the radiator becomes the expansion space, and the sensor blade is above the water level. The car cools off after warming up, and the hose or cap is compromised, and the radiator cannot draw the water back into the radiator when the water contracts as it cools off.
Check the cap, the center metal part of the cap that touches the water is actually a small check valve that relieves under radiator vacuum. it opens, and the water is drawn back into the radiator. it should put the light out permanently if the radiator is serviced correctly.
The water touching the sensor provides a ground through the water and the frame to give the computer the ground it needs to complete the circuit that turns off the light.
Last edited by coupeguy2001; Apr 14, 2008 at 01:28 AM.
Thread Starter
Burning Brakes
Joined: Aug 2006
Posts: 780
Likes: 0
From: New Port Richey Florida
Thanks for the feedback, I ordered a new low coolant sensor when I checked it I noticed the clip is broke. I will make sure I refill the radiator correctly and see if that does the trick. 
