Overheating

[Exahiyan]

I have an issue with my truck in bumper to bumper traffic. The temp gauge gets into the danger zone with the a/c going. Turn off the a/c off and instantly, the temp dropped to the middle area of the gauge. My mechanic checked all of the cooling system and found nothing. Any ideas?

 

[Blown09]

Find a different mechanic?

Also, Year and details of the truck would help. Looks like a 2nd gen, but what engine?
Sounds like the radiator fan isn’t engaging 100%.

 

[DILLARD000]

Year +Model +Engin +Trans +...? MindReading skill here aint't what it used to be.
V8 emblem on the fender in your avatar pic hints at a Gen2 2007~2010 SportTrac.
Overheating while in Stop+GoTraffic or Idling is symtomatic of a
* bad MechanicalFanClutch or ElectricalFanController\Motor
CoolingSystem service should be done every 33kMiles\4yrs:
* new ThermoStat
* new RadCap\ReservoirCap
* new Hoses+Clamps if needed
* reverse hoses on HeaterCore connections
* inspect for Cracks\Leaks at PumpGasket+Bearing & plastic Fittings & plastic HeaterControlValve
* flush + new Coolant
* check operation of Fan+FanClutch or ElectricalFanController+Motors