On a recent service on my 2001 Dodge Quad cab Turbo Diesel the mechanic informed me that the thermal clutch fan was not operating properly. It has now been replaced and I have noticed radical temperature fluctuations between 90C and 100C. Two days ago I pinned it to 110C on a mountain pass with no load. Today the thermostat was replaced and on my trip back up the hill it topped out at 100C. Cools down fast on the way back down the hill. The reason I am posting is that previous to the fan change I recall the temp moving only slightly up or down from normal operating. I am not sure what "noise" distinguishes the fan from regular engine sound. Does the fan need a certain temp to lock the clutch. What am I to expect when I pull our 24' boat up the same grades. Please help the "technically challenged."
......thanks...

 

First thing that comes to my mind on your 01 is A: Check your radiator fins for oil/dirt residue. If you have your crankcase bottle still attached to the front of the engine, and no one has cleaned it out at regular intervals, the fins on the radiator could be clogged. This can cause the engine to run hot under load, and can also effect the operation of the fan clutch due to poor air flow. You definately can hear the fan clutch kick on. It will have an audible "roar".

 

Also check for debris between the intercooler and the radiator. And welcome to the site.

 

That's no joke, My 02 Ram I can hear with the stereo or DVD playing with no problems at full volume. When we first bought our new an 03 Durango I thought the tranny was failing when the fan kicked on. Yes it is temp related. and loud. rrrrrrroooOOOOAAAAAAARRRRRRRRR

 

I pressure washed the fins of the radiator. Three hours of washing all system
rads and I couldn't believe the dirt and grime that washed out. Degreased and washed all of the front. Fired it up and headed up the hill. WHAT A DIFFERENCE!! Took twice as long to get to the operating temperature and I could see the gauge move as the thermostat opened.
I did 100kph up a six mile climb in 32C/90f weather. The needle went to about 97C which is only 2deg over the operating temp. Quick recovery at the top and went to the lowest I've seen in a long time on the way back down. I don't think the fan even locked in. Seemed to have a little more power. Thanks to all of you for your suggestions...........very gratefull....
......even the truck seemed happier.....

 

I've done about five trucks just like yours this year. If you would have removed the radiator you would have gotten even more gunk out of there. I use a good degreaser followed by a long pressure wash session. I finish it with a acid wheel cleaner and a final rinse to make it shine and insures no grease residue. Now you need to see about relocating your "puke" bottle (see mine in my picts), or remove it and extend the hose below the fan wash. That will insure that you don't have the clogging prob again.