PeachParts Mercedes-Benz Forum - View Single Post - Own a E320?? Check your Fan Pulley Bearing!!

unkl300d · #9 09-06-2013, 01:51 PM

Quote:

Originally Posted by vince

This is a common failure (and it is NOT the fan clutch). Every M103 and M104 I have owned has developed this problem after 100K. In fact, all the components with anti-friction bearings (i.e. ball bearings) should be thoroughly checked at 100K. That means idler pulley bearings, tensioner pulley bearings, alternator bearings, fan support bracket bearings. The only unit that is feasible to renew the bearings on is the alternator, and the Valeo alternators make that virtually impossible. I put a stethoscope on each unit at each service and listen for signs of roughness or noise. I am not sure why this occurs. My theory is that the belt tensioner rubber bush hardens over time and doesn't flex as it should, and vibration and stress is transferred to the various bearings. The water pump, P/S pump don't seem to be a problem.

My 1989 300SE with M104 engine just developed a periodical noise that sounds like plastic hitting plastic.
It appears that the pulley that the fan is attached to is not balanced. So I presume that the bearing has gone bad. Fan blade ends seems to hit somewhere.

I need to inspect better and figure this out.

great just found the link w help !!
http://www.peachparts.com/shopforum/tech-help/277378-w126-300se-viscous-fan-bearing-bracket-replacement.html

Thanks to Ivanerrol !

UPDATE 9-9-13

With the help of a very conscientious member, Arthur Dalton, I was able to do some bullet point inspections. I determined that my motor mounts were OK and now I did observe the fan pulley throw itself outward toward the radiator simultaneous to the fan clipping noise (fan extremity slap).
So now I have to price out the fan bearing bracket assembly and figure out how the fan clutch is removed.

I am fairly certain that the radiator does not really have to be removed.

But I wonder whether the belt tensioner is going to be any good after it is loosened. I think I have read that this piece is also a carpicious itme that goes south when you don't want it to.

So, yes, these pulley bearings wear out apparently.

Thanks again Mr. Dalton !