My 2001 Caillac DeVille Has a check coolant level message but when checked is full and no heating problems. Do I have to replace the whole resevoir or is there some way to fix it, maybe by taking it off and using some kind of cleaning solution in the resevoir? Thanks, Mike

If the light is on and the coolant level is full, you have a sticky switch in the reservoir, You might be able to remove and clean or you have to replace switch,,


Sometimes it's part of the Reservoir and you have to replace the whole unit ..

Your coolant level switch at coolant tank may be bad,click here to see.

Does the VAT have to be reset?

WAIT UNTIL YOUR ENGINE IS COLD,YOUR RADIATOR PRESSURE CAP IS LOCATED ON THE COOLANT OVER FLOW RESERVOIR, THATS WHERE YOU ADD COOLANT WHEN COOLANT LOW,YOU POUR COOLANT IN THE OVER FLOW RESERVOIR UNTIL COOLANT LEVEL REMAIN AT FULL COLD MARK DONT OVER FILL OVER FLOW RESERVOIR, WHEN COOLANT LEVEL STOP DROPPING WHEN ADDING COOLANT AND COOLANT LEVEL STAY AT COLD MARK ON THE RESERVOIR YOU RADIATOR HAS THE CORRECT COOLANT LEVEL IF COOLANT LEVEL KEEP DROPPING CHECK FOR COOLANT LEAKS AROUND RADIATOR AND THE TOP AND BOTTOM RADIATOR HOSES, LOOK FOR COOLANT LEAK AT WATER PUMP GASKET OR SEAL OR LEAK AT WATER PUMP WEEP HOLE IF YES REPLACE WATER PUMP.

This item is located in the resevoir, by the brake master cylinder. The Northstar has a head bolt problem, that allows compression gases to enter the cooling system, and that blows out coolant. Loss of heater, loss of coolant, eventual overheat are common symptoms.

But, top up and see of the issue comes back. If it does, have the cooling system checked for exhaust gases..... Extremely expensive to fix CORRECTLY.

NEED TO MAKE SURE YOUR COOLANT MIXTURE IS CORRECT AND BE SURE TO
CHANGE THE THERMOSTAT BECAUSE AFTER A MOTOR OVERHEATS THE WAX
DIAPHRAGM IN THE THERMOSTAT BECOMES DISTORTED

air lock in the system
have it professionally bled out at a radiator shop

No coolant has to do with heat. freon has to do with ac. Now when you said your ac AND blower doesnt come on right away are you saying it does this ONLY when its on ac or when its on heat too. I would first change out your coolant level sensor or add coolant (which you said was fine) and see what happens. but im sure they are not in relation as the blower motor is on its own circuit

the floater inside the coolant gets stuck t wont overheat it is just a pain to see the light all the time

cooliant level sensor at the bottom of ur cooliant tank