2001 Dodge Durango Over heating

2001 Dodge Durango start over heating all of a sudden it has 177000 miles. Took it to auto mechanic had system flushed and pressure tested, replaced Radiator,Thermostat, Radiator Cap,Fan clutch,Coolant Temperature sensor, Water pump, secondary Auxiliary water pump. After parts were replace (bled air out of system each time) and the truck is still overheating. ( IT ONLY OVER HEAT WHEN DRIVING ) When at idle in park no over heating. The overflow tank keep filling up causing the truck to over heat. The Electric Fan Work fine, I even turn AC on while driving to try to keep it from over heating ,temp still goes up 3/4 of the way before I turn vehicle off. I let the vehicle cool and drain coolant from overflow tank. I can only drive about 1\2 an hour before it start over heating.

Any help is greatly appreciated thanks

Turning on the AC isn’t the best way to cool the engine. It does usually turn the radiator fans on, so that is a benefit. But AC, it heats the engine more, as heat from the passenger compartment is dumped into the engine compartment. And the AC compressor itself adds load to the engine. If you want to do something temporarily to cool the engine, better to leave the AC off, and turn on the passenger compartment heater and fan to full heat, Max fan. The heater unit inside the passenger compartment is piped with coolant inflow and outflow and really just another smaller radiator, and will cool the engine quite a bit. The downside of course is that it will heat the passenger compartment correspondingly. Roll the windows down I guess.

But what is causing your truck to overheat? One thing is certain, comparing to when it worked to when no, either less heat is being removed, or more heat is being added. Some ideas:

More heat added

  • Engine timing – check both ignition and valve timing.
  • Head gasket compromised – chemical test for exhaust gasses in coolant.

Less heat removed

  • Even though new, you may still have a bad radiator cap, or it isn’t sealing properly.
  • Same w/the thermostat. The new one could be bad. Check it opens ok in a pan of hot water.
  • One of the rubber coolant hoses could be constricted or plugged up with debris.
  • Radiator is plugged.

For the last three, a trip to the local radiator shop is probably in order.

Also, you might want to repost this in the “Repair and Maintenance” section. Look over to the right on this page, where it says Topics.

Thank you I will post it now