Belt Tensioner Pulley

[John Plut]

I'm replacing the poly-v belt on my '88 260e and have the old belt off. The tensioner loosened up without a hitch but I have a little concern about the tensioner pulley.

The pulley doesn't seem to have excessive movement and spins freely but it makes a whirring sound as if it needs lubrication. Is this normal? Is there any way to lubricate the bearing? It seems to me that the bearing is probably sealed and can't be lubricated. Is it worth replacing the bearing?

Thanks!

John

[Gilly]

I guess I wouldn't get too worked up over it if no noise was present with the old belt. They'll sometimes sound wierd when unloaded. If you're really concerned, you could remove it and try getting some oil to go into the sealed bearing, or just replace it, it's available seperately. Usually the tightener will junk out before the pulley itself will, and the new tightener comes with the pulley. You may want to check the fan hub bearing, and also the idler pulley that's on the fan hub bracket,( the ribbed pulley just towards the passenger side of the car from the fan hub). Of all the pulleys on the car, I'd say the fan hub is the most prone to wearing out, probably a toss up between the fan hub bearing and alternator bearing noises.
Gilly

ps It may be more understandable to refer to the belt as the serpentine belt, I know MB calls it the poly V belt. Serpentine belt makes it alot clearer what type of belt you are dealing with.

[John Plut]

Thanks for the info. I just shot some grease in the bearing using a grease gun with an injection needle. The seals on this bearing are hard plastic but there is enough of a gap along the outer edge of the seal to get the needle in. The bearing is smooth and quiet now. Time will tell for how long.