1. Lets establish that Im older and dumb when it comes to anything other than changing oil, fluids and agpping plugs.

I have a 2005 Durango with 46,000 miles on it and this spring on a short trip it started to overheat. I turned on the heat to make the fan come on and send some of the heat to the heating system. Sounds crazy but the engine cooled down to the center (normal) on the guage.
Over the summer I have checked the thermostat, fan, fan clutch, flushed the radiator, (fluid levels dont go down), changed oil. Engine still starts to overheat after about 15 minutes at 50mph until i turn on the heat.

It has to be something electronic but there are no engine warning lights on.
I am open to any and all suggestions. Thanks

 

Welcome to DF

I didn't see if you have the 3.7 ,4.7 or the 5.7 engine.

 

3.7 I apologize

 

Happened with my 5.7, had to replace the radiator.

 

You may want to hook it up to a starSCAN tool to check the relays (I forget the particular relay that I read about last month) on the CAN bus. Did a check engine light come on or a MIL?
FF

 

Thank you both. The check engine light came on one time when the problem originally occurred and never returned. The vehicle drives about 15 miles and warms up to the mid mark on the guage and then starts to creep. If I stop at a light it will rise faster. If the ambient temperature is below 60 degrees it takes longer. Over the summer months i would turn on the heater front and rear and the engine temperature decreases to mid mark and if the outside temp was 100 it would creep up at the most half way from mid to highest mark.
The durango was bought new in january of 2005 and has 44 000 miles. I do not have a dealership any more and I am leery of going to some of the mechanics around my town. I am going to check today on finding someone to scan the engine and read faults. Im convinced its something simple like a relay. Ill repost next week after i find someone to scan. Unless there was a factory defect on the radiator blocking a portion of the coil I dont understand why that wouldnt have showed up long ago. Thank you

 

You can do the key dance and the P codes will show on the odometer. Turn the key to start (engine not running) from off three times ending in start and the odometer should flash and P--- (P followed by three numbers) will appear for a few seconds. Most auto places, such as NAPA, will scan it for free.

- It was the electric fan relay on the CAN-B and have them make sure the compressor clutch engages with the A/C per the article in Mopar Tech magazine.