M104 Fan Clutch test?
 

I have done a couple of searches and come up with various opinions about how to check if the fan clutch on an M104 needs to be replaced. Anyone have the definitive answer?

~dnm

I could tell mine was going by the low level rumble, clatter while idling. Not very scientific but effective. How many miles on your car? The popular opinion is they go after about 200,000 miles. Mine had 193,000 on it at the time.

I had seen that thread before, but I was wondering if there was a definitive way to physically test the fan clutch. I had heard that if the fan moves more than 90 degrees when the engine is warm, than the clutch has gone. Is the this true?

~dnm

even the cd's don't have one. what is the symptom you are trying to alleviate anyway?

The car just generally runs warm (80 - 85) and gets hot in traffic. (100). The radiator has some cool spots, but I wanted to check the fan clutch before I jump in on a new radiator or to raplace it while I am in the neighborhood.

~dnm

i would say that's normal behavior. you can tell it's working if you hear the characteristic roar at around 100C. do a search for stu ritter's comments on the fan clutch and a modification to lock it temporarily for summer use.

BTW, one side of the radiator is normally hotter than the other. only sure way to check for cool spots is with a non-contact IR thermometer. if you are uncomfortable with the high temps you can install a "cool harness" which makes the aux fans kick in earlier. if you really want to go nuts you can install a tropical version of the fan clutch - do a search on member bongc36. he has a c36 too over in the philippines and had problems in stop and go traffic. the tropical fan clutch worked like a charm...