Question about 2002 GMC Yukon Denali
Your heater core more than likely needs to be replaced unfortunately. If the engine is heating properly and there are no freeze plugs that have been popped then that is your most likely problem.
Posted on Jan 07, 2009
SOURCE: 2005 GMC Sierra Overheating
If your sure there is no trapped air in system after refill and air bleed off, is fan clutch pulling good air thru radiator? Even if it is, the heater should have coolant as hot as what temp gage is showing! Try backwards flushing heater core (dex cool is notorious for plugging these up). There is a TSB for cracked cylinder heads from GM for unexplained coolant loss.Remove drivers side valve cover, and look at center three head bolts for coolant around them, if coolant has been getting in thru this suspect area, there will be a milky/pudding like goo under valve cover and on head. GM had a company called Castec cast these and the areas near the head bolts were found to be too porous (NO recall YET!) Ya, you guessed it, replace heads! Unfortunately, if its gotten hot to many times, it has probably hurt the heads/gaskets. Hope this helps. PS: The castec logo is under the rearmost pair of rocker arms,may have to remove them to see.
Posted on Feb 05, 2009
The problem is most likely 90% head gaskets but could be intake manifold gasket leaking too. Intake gasket has to be checked when intake is removed. Might find problem there if not continue and remove heads. Bars Leak will not work.
Posted on Apr 03, 2009
UNDER THE HOOD IN A RECTANGULAR SHAPED BLACK BOX. UNDER THE COVER IS THE DIAGRAM FOR THE FUSES AND RELAYS. HOPE THIS HELPS. KEEP ME POSTED PLEASE. BEST OF LUCK. THANKS FOR USING FIX-YA
Posted on Apr 30, 2009
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