I have an 05 XL 4.2 V6 for little less than a year. Recently noticed temp gauge climbing when AC on. Had coolant flushed, thinking it may be stuck thermostat or fan clutch. Heat and defroster never worked well ( practically no heat ) Any suggestions ?

 

Water Pump & T-Stat are possible causes.

Wayne

 

If you are not low on coolant, thermostat would be the 1st place I'd start.

 

Has it been off road lately if so check the radiator and by the fan for mud insulating the radiator from cooling down