03 yukon overheating

[DDDYSGOODGIRL]

hello every1 im new so bear with me....i have a 03 yukon 5.3 last week i was driving no a/c on and i lost all engine power but everything was on...i guess its called limp home? mode so i pulled over waited about 15 mins and started it again and was able to drive home...but temp gauge was reading almost 260 (which is in the red for my truck normal is around 210) my brother in law came over and checked it out said it was my fan cluch...so i got a new one put in. one week later it did the same thing(but ran normal all week) had it towed home brother in law suggested we change the thermostat so i purchased a new one and he installed it i have no way of testing if this worked unless i go driving and basically get stuck again...but i was told i can test the thermostat if i boil it in water and it opens up then my old one was good and not the problem...so i boiled and and it opened up...please help!

 

[alacran]

im no help but if ur truck does over heat turn the heater on that will remove some heat from the engine.

 

[chip]

Water Pump?

Coolant levels?

Engine Milage/Bearing Health?

Pull Codes?

 

[Volant1]

Hey welcome to the forum, If the fan cluch was replaced and the problem stopped for a week than came back I would point the problem at the cluch again maybe its a bad part or a install issue. A thermostat is a pretty cheap part so if you were going to take it out you might as well upgrade or put a new one in, Do you know if the fan is kicking on? also check the fuse this is always the first step

 

[blueflamed03]

when hot, is upper hose hot too, to see if your getting good flow...also may be plugged radiator...maybe time for a flush.

 

[chip]

All great ideas.