We are in the process of swapping engines into my daughter's '91 240. When we pulled the old engine out, the cooling fan had one of the blades broken off. We picked up a fan from the junkyard that came off of a 740. However, the clutch on the fan seems stiffer than the clutch on the original fan. This is at temps around 75F.

The question is, how can I tell if this clutch is working properly? Another difference is that the 740 fan has 8 blades instead of 6 that was on the original. I really doubt that the difference in number of blades should make any difference but I really don't know how to tell if the clutch is bad or not.

Any help would be appreciated.

 

The 740 fan clutch is probably in better condition than the 240 clutch. In general stiffer = better. Number of fan blades shouldn't make any appreciable difference.

I've always used the test-while-running method to check a fan clutch's condition. Wearing a thick glove (i.e. leather work glove), try to stop the fan while the car is idling. If you can stop it without too much pain then the clutch is shot. I know you don't have the engine in the car and running yet, but I think you're OK with the 740 clutch. Also, if the car runs hot only at idle then that's a good indicator of a bad fan clutch. Good luck.

 

Thanks for the reply. Wow! You are brave. I wouldn't go sticking my hand anywhere near that thing when idling. I was actually wondering if it perhaps was a 'tropical' clutch. I would expect that they would be stiffer.

I live in the Chicago area and it (normally) isn't too hot here. The car has never had any overheating issues and the air conditioner hasn't worked since we got the car five years ago. Generally I feel that the cooling system was never strained in this car.

Anyway, thanks for alleviating my worries. We'll go with the new one.