ok so here’s my problem


I have an 07 GT, the other day I was idling with the AC on and I overheated.


I replaced the thermostat and the water pump just to be in the safe side.


pressure test was fine


I’m not leaking any coolant. There was a 30 degree difference between the top radiator hose and the lower radiator hose, so I know it’s cooling

Fans are fine, the shop used their computer to turn on the fans at high and low no issues


fans kick on when they are supposed to when engine is running


it takes a while for it to overheat, maybe 20 mins idle before The gauge starts climbing


their computer read the CHT sensor as 253 degrees, it did not go up or down under load ( bad sensor?)



Since replacing the water pump and thermostat, the car hasn’t boiled over, just the gauge slowly creeps up after idle



I never had overheating problems before , it just started out of nowhere .


could it be a clogged radiator?


any ideas?

 

It's possible. You could try flushing the whole cooling system to see if that helps. You could also try pressure washing the AC condenser. It sits in front of the radiator and if the fins are clogged up with dirt and dead insects, the condenser won't allow sufficient cool air to reach the radiator.

 

Cop cars often idle with A?C full on for extended periods; Never saw one boil over. Why? They have no more room for huge oversized radiators or other gimmicry under hood than standard-build models.

Suggestions above are sound. I would investigate availability of high-output water pumps (after determining condition of radiator), smaller water pump pulley (often found on "heavy duty cooling package" cars. Install lower temp. thermostat than factory-recommended; try 160`, despite advice to contrary; my EEC-IV vehicles all work fine with them. A half-opened 190` or 200` may restrict flow enough that the cooling system cannot "catch up". Look in to changing radiator to multiple-core, my '94 GT has only one core (originally, but now 3-core). Adding thicker radiator might necessitate getting rid of the cumbersome Ford electric fan and catch bottle, as I did, but this is not a job for the inexperienced. My '94 got hot as hell before the fan turned on, gauge near top-end, took 10-15 minutes to drop to lower end after fan turned on. I used an Explorer-spec fan clutch and fan blade after making room for them; temp. gauge now sits motionless in the center regardless of operating conditions. AC rarely on higher than "2". 180` thermostat.

Ask, if interested in seeing pics.