Engine Cooling problem
2000 Dodge Durango V8 Four Wheel Drive Automatic 161000 miles
durango runs normal temp at highway speeds. But at low speeds it climbs to about 200-205. However when pulling steep hills at low speeds temp has gone to 220. Heaters dont blow very hot. Just got back from dodge dealership where both head gaskets, fan clutch and plugs were replaced. Did this before repairs but was also pushing coolant out the overflow, NO coolant loss now though! Just fluctuating heat hand. Also do you know at what temp my electric fan should kick in? Right now it gets to about 210-212 before kicking in. It will kick right on with ac or defrosters turned on. Can clogged heater core cause irregular temps? Was fine for day or so, buuuuuutt. Not now any help would be awsome.
Electric fans are turned on by the engine computer at 212 degrees, and off at 198 degrees.
Check the radiator fins to see if they're crumbling away. Too much antifreeze concentration will reduce the coolant's ability to transfer heat. Water can hold and transfer more BTUs of heat than antifreeze. Straight water is better at cooling the engine than any antifreeze, but antifreeze is necessary for freeze protection and for the additives which include water pump lubricant and anti-corrosion chemicals.
Make sure no one removed the shroud around the fan. That will allow air to bypass the radiator.