I have a 2000 Durango SLT 5.9 4x4. When i first start it in the morning and go for a drive the temperature stays on 130 but when i take it off roading and go real slow like around 5 mph the temperature gets up to where it should be around 200 degrees. Would a stuck open thermostat cause this problem? I also noticed the mechanical fan runs constant from when i start it until it warms up. Not sure if this is a problem or not. I've tried spinning the fan by hand and it goes about a quarter turn then stops. Any ideas? Thanks, Joe.

 

Check the electric fan. Turn on the A/C and see if it is turning. It is located between the radiator and the clutch fan on the 2000-2003. No electric fan on the 1998-1999.

Mine always ran low when it was cold in the morning, however yours could be a worn T-stat and if you replace it I would go to a 180 F.

 

My A/C doesn't work but when I turn it on the fan doesn't turn on if i remember correctly. I figured the thermostat was stuck but i figured i'd ask you guys before i replaced it. I'm going to be hauling a good sized trailer tomorrow so we'll see if that warms it up or not.

 

My fan has always run full on unless, like in winter it idles for 5-10mins and is a full operating temperature, or I drive 1/2 mile. It will run for a little bit even if it has been shut off for only 10min. I think it was the way the fan clutch was designed. Yours could be going out. It would be a lot easier to replace that then the thermostat. I replace my thermostat because some mechanic replaced it and over torqued the bolt in the manifold causing it to leak. That was a pain to fix.

 

It doesn't matter if your A/C is working or not, what I am stating is when you place the dial to "A/C" the small electric fan should turn on and you can see it and hear it. If it is not turning on then see if it's corrosion or a bad fan motor.

adukart<-----The clutch fan is a different story.

Usually during cold start up the manual clutch fan will engauge because the fluids in it have settled and until the disperse the fan is engaged. So it will sound like a rocket ship for the first couple of blocks. It can do this after shut down because the heat from the radiator settles the fluid as well, but again it shuts off quite quickly and goes back to normal.

 

ok, thanks for that explanation hydra, I have always wondered how it works.

 

My electric fan does turn on when i turn the dial to A/C. I have another question though that i just remembered that you might be able to answer. When i turn the dial to A/C the windshield wipers come on for 3 cycles then turn back off. Have you ever heard of anything like that before? Seems very weird.

 

Most likely that sounds like a CTM module personally. The module runs all the internals like the radio, head lights, window wipers, and ect....

Seeing that your electric fan is working right and your clutch fan is a little on the fritz, I would replace the thermostat. I would not buy a Fail Safe brand. Personally I would get a DuraLast T-stat from Auto Zone part number 15358 is a 180 degree T-stat. Now it is a little lower temp so your heater won't be so hot but your motor will last a lot longer.

 

+1 Hydra, The 180 T stat will make your heat less hot. but it mostly causes issues for the rear heat. the front heat should still work fine.

And just throwing this out there you say its getting up to "around" 200 degrees? Isn't the stock t stat on a durango 195 degrees Fahrenheit? So its only running slightly higher if any at all?

 

Thanks Hydra, do you have any information on where that module is located? Also today i checked the codes on my Durango for sh*ts and giggles and i had the P1281 code which is a "taking too long to warm up" code and i read on this forum that some people that put in a 180 thermostat will get that code and i live in Maine so it gets pretty cold during the winter so I don't know if putting in a 180 degree thermostat would be a great idea but if you say it's fine that's the route i will go. Thanks.