I am out of town with my Tahoe and getting the message "Engine Coolant Hot" on my dash message system.

When it pops up I notice that the temp gauge goes up almost to the red line. Also the air conditioning stops being cold.

If we wait a moment or we toggle the air conditioner on and off it seems to fix itself and the temp gauge instantly goes all the back down to a normal range.

Any thoughts on this?

  • This is happening while you are driving down the road? Or when sitting (or anytime)? I assume the Tahoe has the 5.3L engine and clutch fan (not electric)? And to clarify, when you toggle the AC switch, the AC will then start blowing cold air? Check to ensure you have the proper coolant level as well. Commented Jul 5, 2015 at 19:13
  • Did you ever get this fixed or have any further information for us? Commented Jul 28, 2015 at 1:33
  • Hey @Paulster2. Late response here. Switching on the air-conditioning or recirculating buttons does not necessarily solve the problem. It just seems to go in and out. For example right now it's still says engine coolant hot and now there is some cold air coming out. But normally, while it says engine coolant hot there is not cold air. Currently the temperature gauge is close to 260. But as soon as the engine coolant hot sign goes away that number will go all the way down to less than 230.
    – CRAIG
    Commented Sep 10, 2015 at 22:29
  • OK. Actually, in that instance, when it switched the engine coolant hot I did hit the little snowflake button and the air did start to cool down so I don't know if that's a coincidence or not but that is what happened
    – CRAIG
    Commented Sep 10, 2015 at 22:32

1 Answer 1


We have a 2004 Tahoe and had the same notice appear on the dash. Took it to the dealer after the notice restarted after Tahoe had been sitting overnight. Dealer found no external leak evidence, and told me leak it is likely internal (gasket?). Service did most testing to determine if internal leak existed. NADA. Dealer had Tahoe ~1 week. Service refilled coolant and no loss overnight. So we are back to increased vigilance.

Seems time to replace the Tahoe after 13 1/2 years. Any repair that involved disassembling engine will be expensive!

  • Greg. I am thinking it's the manifold gasket. All seems to point there. Also I am having potential fuel pump issues.
    – CRAIG
    Commented Aug 17, 2017 at 15:33
  • If there's a coolant loss, don't forget the Castech head issues. The heads with 706 casting were prone to crack, usually around oil drain holes.
    – Jan
    Commented Jan 15, 2018 at 18:36

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