Bearings Shot

[athflying79]

When I shut the car off, I can hear something that sounds almost like marbles rolling in the fan belt area as something comes to a stop. I thought it was my water pump on it's way out, but now I'm not so sure.

Isn't that sound the sign of a bad bearing somewhere??? I'm assuming the steering pump and the alternator both have bearings somewhere near the pulley...how often do they go out?? What else should I be looking for??

[Dave M]

Are you sure its in the front of the engine? Did you have someone turn the car off while you stuck your melon in the engine bay to locate the source? You may find such a noise coming from the rear as the engine winds down and the flywheel rattles a bit.

OOOps, noticed its an auto, so maybe this is not as prevalent. Anyhow, my manual does this from time to time, not too concerned.

Dave M

[ahager]

I have experienced a similar sound on my 1990 535 Manual 5 speed. I bought the car when it had 130k miles and it has 240k now - still makes the same noise. A local reputable BMW mechanic thinks it is the main trans bearing chattering as the driveline stops when the enginer is turned off. I dunno - it makes the same noise with the clutch in or out. Probably a bearing somewhere!

[winfred]

one way to check accessory noises if you don't have a mechanics stethiscope is take a long screwdriver and put one end on something that may be making noise and the handle end to your ear. or you could take all of the belts off and spin every thing by hand

[Kalevera]

Axial bearing play can be felt in the water pump. Remove the fan belt, grab the pulley and see how much movement or notchiness is in it. How much is sort of relative -- some new pumps have an almost imperceptible amount of play. The other sign of a bad pump, leaking past the front bearing, probably wouldn't manifest in a noise as coolant has some lubricating properties.

When the P/S bearing goes, it makes what I'd call a cracking noise while running, usually not load dependent. This is a bit of a different sound from impeller and seal problems that result in the whining and groaning typically associated with bad pumps.

Andy is describing dual mass flywheel rattle, not applicable in this case.

If the noise is related to a front accessory, it probably can be heard while the car is idling or under load. Find a helper to spot it?


best, whit