2002 Yukon Denali / Low Coolant Warning Light

[Thomas Hennigan]

I have a warning message "Low Coolant" that popped up yesterday. The truck is running like a top, nowhere near overheating, and the coolant overflow reservoir is half full. The truck has 265k on the clock. Any ideas? Could the coolant be low in the radiator and still half full in the overflow tank ?

 

[OR VietVet]

Likely is the sensor in the bottom of the cooling system reservoir. Sometimes they can get stuck or just stop working. If you look at the reservoir at the bottom close to firewall and at the bottom corner toward the engine side of it you will see a plug in for the connector. Have to get whole tank to fix that.

https://www.rockauto.com/en/moreinfo.php?pk=8364964&cc=1381047&jsn=877&jsn=877


We recommend that you put all your rig(s) info in your signature so we all don’t have to guess at year, make, model, engine size, trans, rear axle locker…….etc. While you may have posted pertinent info in your first post, you may forget to do it again and the info is needed by us anyway. Makes it way easier on all members that attempt to help, to have that info right up front. It is also recommended that you take a pic of your RPO codes, on the inside cover of the glove box, and post that image in your signature. All this info will greatly help those that will try to help with a problem.


If there is any other info, like upgrades, mods or recent mechanical/maintenance work done, that would be helpful in any post as well. Too many times a question is asked by the poster and after about 10 responses we find out that the poster has done recent work to attempt to fix the problem or work that was done that SEEMS not related to the problem.

 

[Thomas Hennigan]

Thanks!