8.3 Fan clutch rattle

[Edelbroke]

I bought my first 5 ton a few days ago. 1991 BMY HARSCO M931 A2 WO/W, 8.3 Cummins, Drove it 160 miles home. No problems other than there seems to be a rattling sound coming from the fan clutch area when the truck is at operating temp and idling. It may go away while driving but I don't know, just cant here it. At idle when cold it doesn't seem to do it right away but will slowly make a random rattle and gradually get worse. The truck has an air leak somewhere, gauge is always at zero from being parked over night. I've searched on here and on the web about it could be, found a thread about some bolts falling out internally which seems like something that could make this sound but I don't know. I also saw a thread about possibly having the wrong belt, What I would be most interested in is if there is a non air actuated fan from another Cummins large truck or any other truck I could replace this style with? Thank you for any help

 

[simp5782]

Rebuilding it is pretty cheap. You can source the parts in it via the TM thru Ebay mostly. I think total rebud cost is under $100. The rattle when they get some play in them. Some of them have grease fittings on them as well

If you want to hear the rattle with the fan operation simply close the primary air tank I believe. It will not allow air to go to that shutterstat.
This makes the fan clutch engage. Or take the JIC fitting off the line up by the firewall and either use a #6 jic cap or your hand to close the pressure off