I have an 07 Yukon Denali xl 6.2l. My truck temp is runni...


I have an 07 Yukon Denali xl 6.2l. My truck temp is running around 230 to 240 degrees. If I get on the highway it will at 210 degrees. Its been running like this for a few days now. I also noticed the rear heat takes longer to get...

I have an 07 Yukon Denali xl 6.2l. My truck temp is running around 230 to 240 degrees. If I get on the highway it will at 210 degrees. Its been running like this for a few days now. I also noticed the rear heat takes longer to get warm or doesn't get warm at all. Today I noticed that the driver heat is going from hot to cool. My [ac compressor](/topics-ac-compressor-gmc/) needs replacement but its getting cold out now so thats not a necessity. I replaced the [water pump](/topics-water-pump-gmc/) maybe last summer. What could be the issue Mechanic's Assistant: Has the vehicle ever overheated? And when was it last serviced? It hasn't over heated since I replaced the water pump last year Mechanic's Assistant: Are you fixing your Yukon yourself? What have you tried so far? Yes I would like to fix it myself. If I can narrow down what the issue is and I don't have to put the truck on a lift Mechanic's Assistant: Anything else you want the Mechanic to know before I connect you? Haven't tried anything so far

Automotive Expert
Hello, my name is \*\*\*\*\* \*\*\*\*\* I'm sorry to hear about problem. Ignore phone call prompt and there may be short delay between replies.
Automotive Expert
The fact it overheats other then on highway would usually point toward a partially clogged radiator or thermostat. With additional information of heat not working, that may or may not be related. IF so it is possible you have air in system due to head gasket causing the cold heat. I'd start by replacing thermostat since its typically first place to go if that doesn't help then check radiator for hot/cold spots which would indicate blockage. Also make sure cooling fan is working properly. Let me know how it goes or if you have more questions, thanks.

Ok, so can you steer me in the right direction to find out what the problem could beIt hasn't overheated, It runs hotter than usual at around 240 degrees, it normally runs at 210 degrees.
Automotive Expert
High speed fan should come on at 220 so I'd start by making sure high speed is coming on, if so then replace thermostat. Let me know how it goes, thanks.

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