Ok here is my stumper of the day. I have a 2000 Dodge Durango Sport V8 4.7L.

About a month ago it started overheating while I was driving it from Houston to San Antonio for work. I work for the railroad and have to drive lots of miles every week and this is my only mode of transport. Back to the story.

My fan clutch was sounding like a small turbo prop taking off so I figured that was the problem. I promptly went to Oreillys and purchased a new fan clutch and put it on. The problem was solved for about 1 day because I didn't drive it on the highway. I then headed home and it began to overheat again. Now I have to qualify that by saying it didn't overheat it ran hot. Temp gauge would go up to about 3/4 and stop. I thought it was the thermostat. I had it changed also and still the same problem. I drove it through Missouri on vacation this past week and with the cold temps up there no problems really but when I got back to Texas today it heated up and even overheated especially when I ran the AC. It kind of does the opposite when I come to stop lights the temp goes back down but when on the highway it goes back up. I checked for codes and I got a P0108 code. Not sure what that means.

Please help. Did I put the fan blades on backwards? Could that be a problem?
I don't want to spend all my money doing what everyone else has done with head gaskets and water pumps for the problem not to be fixed. Help if you can.

 

Did you use a stocker stat?

Did you check the coolant fluid level?

Did you burp the stat?

Did you check the fluid again after the burping process?

IndyDurango

 

Yes to all the questions.
195 degree thermostat.
Did a complete flush and fill on the system.

 

Check out the radiator with an IR thermometer. Temperature changes should be gradually cooler from the top to the bottom. Any large fluctuations in temp indicate blockage. Check out your water pump. If there is any play in the pulley it is too much and needs to be replaced. Also if the radiator is dirty it can inhibit cooling so some simple green and a hose are your friend. Wash it out from the backside of the radiator to prevent pushing contaminants further into the core. Also don't use high pressure on the rad. The fins are delicate.

 

Ok so here is another question. Can the water pump go in and out? I stopped at a rest stop to let the engine cool and I took off the cap and added fluid, started the engine and coolant was flowing pretty good but then it kind of stopped and started to gush out of the radiator hole. Does that give me anything to go on? Also I thought about purchasing a Mopar fan clutch with max cooling instead of the OEM one that I bought, would that help at all?

 

The water pump is belt driven so it is all relevant to the engine speed. Pull the belt and grab onto the fan and give it a wiggle. Again any play means that the bearing is worn and the pump must be replaced. There is also a weep hole on the pump. If there is a leak from the front of the engine there's a good chance it is coming from that hole. Inspect as best you can and replace if necessary. As far as your cooling fan. The OEM fan clutch does a damned good job at cooling the D down. You are overheating more readily at highway speeds which rules out the fan clutch anyway. I would recheck that T-stat and see if it was bad out of the box. FYI next time you replace a T-stat put it in a pot of boiling water to verify that it opens and closes completely. I've had them fail partially open in the past and fail within a week of install.

 

So the max cooling fan clutch from Mopar is overrated??? Is that just a ploy to get more money outta me? The pulley wiggles a little especially since I replaced the fan clutch. I am going back to the fan clutch because when the D was hot as hell on the highway the fan clutch still seemed to be moving at engine speed and when I stopped the fan still moved with some resistance. I thought when it was hot the coil would allow it to move more freely. Am i wrong about that and what about the code I am getting?

 

The engine code index is at the top of the forum. I forgot you wrote about a cade.

P0108 Map Sens Voltage Too Hi

Chances are the MAP sensor is fried. Replace it and replace the water pump. Yes that clutch is not necessary. I figure if you do a ton of towing it would be worth the money but typically that's not the case with an SUV owner.

 

Ok so will replace the water pump and where can I get a MAP sensor at a decent price? Thank you by the way for your help with this stuff cuz it has been driving me crazy.

 

I wouldn't replace any sensor on the D with anything other than OEM. Other brands are generic sensors with the right connector attached to them, therefore they won't necessarily have the right internal resistance.