300 sdl busted pulley and damaged radiator fan - PeachParts Mercedes-Benz Forum

julio.garcia.fc · #1 11-10-2014, 10:55 PM

My belt tensioner pulley "fell out" yesterday. The bearings made a horrible noise and the pulley came out and rolled down the street. In doing that, two of the little tabs on the radiator fan assembly broke off. I am not sure if I should not worry about it, break off two on the opposite end to keep it balanced or replace it. Any suggestions? The image here does not show the broken tabs very well, but it should give you an idea of what I am talking about.

MBZ123 · #2 11-11-2014, 06:00 AM

You're gonna want ANY rotating mass as close to balanced as possible. Didn't see any attached image, but if yours is metal, swap out for later plastico. If plastic already, replace with new or used/undamaged.

MBZ123

julio.garcia.fc · #3 11-11-2014, 10:17 AM

ARGH! I am really having a time posting. I lost my initial post somehow, and the image on the second one. OK, sounds like I should look into a new fan. Let's try the image again:

julio.garcia.fc · #4 11-11-2014, 10:19 AM

P.S. it is really the fan clutch that lost a couple of tabs.

MBZ123 · #5 11-12-2014, 04:13 AM

O, misread that. In that case, probably not an issue since the missing mass is minimal and located so close to center. I wouldn't worry about it. I'd be more concerned with why the failure occurred and fix it proper. That had the potential to be a $$$$ disaster.

MBZ123

julio.garcia.fc · #6 11-12-2014, 10:36 AM

Thanks MBZ123. I will do that. Could it be that after all these years the bearings just gave out? Also, when I changed the fuel filer, some diesel spilled in the area. I cleaned it as best as I could, but could it have leaked inside and dissolved the grease in the bearing? It should be well sealed, I would think.

P.S. How the heck do you change that filter without making a mess?

Anyway, thanks.

MBZ123 · #7 11-13-2014, 02:35 AM

It's almost guaranteed bearing failure was at fault, you mentioned hearing something horrible. Sealed bearings are robust, but they can't last forever in such a harsh environment. The pulleys are replaceable as are the bearings in the pulley, though they're harder to track down separately. I would suggest replacing the entire pulley, they're pretty inexpensive.

On fuel spillage, some fuel is gonna escape when working on that system regardless. A small amount of diesel isn't the reason your bearing failed, though. The main filter is at the high point in the circuit so spillage should be minimal. I'm sure a shop towel around the filter should suffice. Having the new filter filled up and within arms reach to swap right in will minimize the time the circuit is open.

MBZ123