Tempure Gage Shows Hot,turns Off Ac,and Then Starts To Close Down Each Cylinder Until The Motor Stops. Water Is Not Hot! Turn Motor Off About Ten Minutes Or So,will Crank, Run Fine. Maybe Ten Minutes, Two Hours Or Two Days? 4.2 1999 F-150 2wd Apple6

 

Welcome to FTE!

Any check engine lights? Could be a bad t-stat, clogged/bad radiator also a possiblity. How many miles on the truck?

 

Thanks Triton_2002 New Fan,t-stat U-name It Water Temp Is Not Too Hot Several Dealers Want To Start Changing Parts,my Money.

 

there is a water sensor that sends a signal to the computer of "water temp". if the signal says the water temp is too high, the computer shuts down the AC, then it turns off every other cylinder and acts as an air pump to cool motor. if temp continues to rise, the computer shuts down the motor. water dont have to be hot, thermostat dont have to be bad, the sensor might be sending a bad signal to the computer.-- i dont know where the sensor is located rigth off, but thats how it works. have them check the sensor.

 

The PCM actually uses cylinder head temp, not coolant temp to gor into fail-safe mode.
There is a temp sensor in the cylinder head that actually measures the temp of the head itself since that if the coolant level gets low enough, it won't hit the sending unit and will not read HOT (trust me, My Mustang did this years ago, then got the revs up to about 3000rpm and the temp gauge pegged at 270 and got new head gaskets )
Perhaps you could find a buddy with a tuner like a Predator that will show real time data from the pcm to see what is actually going on.
You may just have a bad sending unit somewhere. Any engine lights or is the gauge pegging?