2001 Suburban low coolant, but not?

mitchellbk

Original poster
Member
Feb 1, 2017
6
Idaho
Daily driver, 280K. A few months ago I noticed the low coolant light on and a 'chemical' whiff came through the vents (we had the heat on because it was winter) - I didn't have extra coolant with me so I just watched the engine temp and made it home without the temp going past normal level. I let it cool in the driveway for a bit, and I come out to top it off and noticed that the coolant level is just a tad under fill mark, but not low enough that would warrant the low coolant light. So I topped it off anyways. A few days later, same thing happened - low coolant light came on, and I checked, normal levels. This happened about once every 2 weeks since then, and I have yet to add any more additional coolant. Doesn't seem to be a pattern either.

Short summary, low coolant light comes on, but I never need to add more coolant. Any ideas?
 

Sparky

Member
Dec 4, 2011
12,927
Bad switch?
 

christo829

Member
Dec 7, 2011
497
Fairfax, Virginia
I'd say coolant level sensor. Are you checking the levels in the radiator, or just the reservoir?
Once it cools down, make sure the radiator level is good. Had a cap go bad on my old S10
so it wasn't drawing from or pushing to the tank. Worth making sure, but it still sounds more
like the level sensor is bad.

Good Luck!

Chris
 

mitchellbk

Original poster
Member
Feb 1, 2017
6
Idaho
eeek, heater core looks like a time consuming job. Do you think by chance it could be the T-hose connecter that's bad at the firewall? While the whole dash is apart, anything else that should be replaced?
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,639
Tampa Bay Area
Whoa, Brother… Put this idea on SLO-MO... just long enough to consider that performing a Heater Core R&R is NOT a trivial repair… but something akin to the interior cabin version of an Engine and Transmission R&R. You could follow up with your own idea about searching out the last possibility of having Coolant getting into the cabin area (although probably not migrating into the vent system) via the infamous GM Design Failure of those Damned Heater Core Hose Connectors leaking along the piping; just inside of the cabin wall and perhaps coming through the upper passenger side Engine Compartment Firewall.

Watch this video first and then do a little close up inspection. If you see Coolant leaking and can sop up any from around these ridiculous fittings… the video will show you how to repair this problem:


If that otherwise proves not to be the case...Watch these videos ...and then think long and hard about whether you want to tackle this absolute nightmare of a job:




 
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