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Low Coolant Level Warning - 2000 Pontiac Montana

Over the last couple weeks I occasionally get a “Low Coolant Level” warning when driving my 2000 Pontiac Montana, especially when at highway speeds. But I am not low on coolant and the engine temperature is generally good (although it creeps up if I get stuck in traffic). If anyone has an explanation for this screwy behavior, I’d sure appreciate a response.

Is your coolant brown and chunky? Dexcool has a way of caking to sensors and everything in your cooling system and can cause false readings. So I’d look into the condition of the coolant to start.

Thanks for the quick reply! I did not realize that Dexcool can cause that type of problem. But the coolant looks pretty normal - red with just a slight brown discoloration. No obvious sign of chunks.

I would get the DexCool out. The real problems are not in what you can see - but in what you can’t.

If you are worried have a coolant flush. Sensors like this worry you more than fixing them is worth. Possibly removing and washing the sensor might help. If your temps are fine and the coolant level is consistently ok try a bit of electrical tape over the coolant warning light. That way it wont shine in your eye and bug you.

I’m going to disagree with that, though you’ll obviously make your own choices. The sensors are there to alert you to problems. If you leave them burning you might miss it if you really do have a problem - in this case, low coolant, then overheating, then engine damage.

Under certain circumstances I would do this, but I would be actually popping the hood to check the coolant frequently as a substitute for having the light to warn you.

Suit yourself whether or not to fix it on an 8 year old car. Most likely just need a new sensor or cleaning it might help. After 10 years on mine I decided it wasn’t worth fixing. The way it works is that the sensor grounds through the coolant. When it is grounded out, the light will be off. If the coolant gets low, it won’t be grounded and light goes on. If the sensor is gummed up or faulty, it won’t ground so light is on. So disconnecting it just turns the light on. You have to take the wire lead and ground that out to shut the light off. I just used an aligator clip on mine but by all means fix it if you want. Shouldn’t be that expensive and just screw in and screw out.

Also, I believe this sensor is in the radiator, but I presume you’re checking it in the overflow reservior. If you have a faulty radiator cap, it can prevent fluid from going from the reservoir to the radiator.

Since caps cost like maybe $8 and you can easily change it yourself, I’d recommend giving that a try.

(I’m sure you probably already know this, but just in case: change the cap with the engine cold, lest you burn yourself.)