medicmandan

I seem to have two different problems, not sure if they are related or not.

1. "Low Coolant" light keeps going off and on. I am not low on coolant at all. Sometimes it is on when I first start the car, sometimes it doesn't come on for an hour so. Occaisonally it will stay on for a couple of days. Coolant level always seems to be the same. I tried bleeding the air out of the system at both valves and it didn't seem to change anything.

2. Cooling fans don't come on when the car heats up. This results in the car heating up to above normal but not overheating. Car is at normal temp as long as I keep moving. Both fans come on when the AC is on.

Sensor problems? Water pump? Thermostat?

GTP Dad

Find the low coolant light sensor and clean it and then reinstall. They get dirty and will continue to give bad readings until cleaned. As for the fans not coming on you may have a bad fan relay that is not turning them on when the pcm sends a signal to do so especially if they come on when the AC is in the on position. I would check and replace the water temp sensor just to make sure that it is working correctly and if that doesn't correct the issue you may have to have the PCM checked for proper operation.

medicmandan

Thanks. I've got a new temp sensor on order and I'll clean the low coolant one when I replace it. Do either need a sealant on the threads for install?

tblake

yes, use a sealant. RTV red usually works fine. Nope pipe dope or teflon tape

__________________
2000 Pontiac Grand Prix GTP
(3.5" Pulley, DHP 1.0 PCM, ZZP 2.5" High Flow Downpipe, MMS Ported and Polished Lower Intake Manifold, ZZP Stage 1 Ported Throttle Body, 180° Thermostat, NGK Iridium TR6IX)


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medicmandan

Thanks.

bombergp

Hey Medicmandan, I also have a 3.1L se, how many miles does yours have?
Have you changed out the nasty dexcool to something like prestone extended life coolant? Dexcool has been a considerable source of troubles, detiorating intake manifold gaskets to premature engine failures and all related cooling system components.

medicmandan

It just hit 100K. I was planning to flush it this summer. I replaced that sensor but it doesn't seem to have changed the fans coming on. When I went to bleed the system I dropped the little screw from and couldn't find it. Took me a week to get a replacement.