Tom. M

Heading home from Sharks on Ice, I noticed an odd noise above the usual exhaust note. It seemed to be coming from the drivers side rear area (but could have been both sides since I was driving).

It sounded like snow tires and was only present above 50mph or so. At first I thought is was the road surface but it was present on both asphalt and concrete and didn't vary.. I could change the tone of the noise a bit by veering left but once straightened out it came back.
I've always thought the bearings would howl more than this sounded but I'm not sure what the 928 bearings (massive) would sound like...

I'll put her up on the lift eventually and spin each rear wheel..anything else I can do to test?

GlenL

Can sound like rumbling.

NC928S4

Can also sound like a cyclical "thwap" or gravely.

Best way is to get wheel off and spin by hand. Listen and feel for noises. Failure should be only on one side allowing you to compare one side vs other.

jheis

When mine went south in made kind of a "whump, whump, whump" noise. At first I thought I'd broken an exhaust hanger and the exhaust system was bouncing up and down - hard to tell from inside the car.

Did a slow drive-by at a friend's shop while a couple of techs listened - right away they said rear wheel bearing.

mark kibort

its a bearing noise. and it will get worse, and better, when you S turn on the freeway. (make sure no one is around)
usually, it wont be felt on a lift or going slow.... its got to be loaded, thats why when you S turn, you load and unload that side. the noise should come and go.

Tom. M

That is exactly what it was doing... hmm....I'll still put it on the lift and see if I discern any difference...but looks like some rear bearings are due (not bad for over 335,000 km's......

mdkelly1

The "whump, whump, whump" description is a good one. That's exactly what my first one sounded like during a 1200 mile drive many years ago. The bearing was pretty far gone and would make that sound regularly, even during short local drives.

The second one (the other side and about a year later) was similar, but influenced more by the load on that wheel going through curves. The sound would vary as the load increased or decreased. The bearing on that side wasn't as bad as the first one, but it still needed to be replaced.

If I had it to do over today and needed to replace one of the original rear wheel bearings, I'd replace both of them at the same time. Just my preference since both of mine went bad close to the same time.

If you have 100K miles on the car and haven't replaced any rear wheel bearing yet, I'd be listening for that sound eventually.

YMMV.

Shawn Stanford

Mine went 'whump, whump, whump', obviously varying with road speed. And, if you ignore it long enough, they'll freeze. That's a pretty good indicator.

atb

Mine made a low pitched whirring noise at 50+ mph that did not change in pitch regardless of speed. Made no noise freewheeling on the lift. When I pulled the carrier, bearing was nice and crunchy when spun. Had the new bearing pressed in by a machine shop and...bearing was nice and crunchy when spun. WTF? Reassembled it anyway. Dead quiet.