Strange Vibration Noise

[mrnine]

Just got back from a 3,400 mile trip up through Nova Scotia to PEI. My '98 318ti performed pretty much flawlessly. We had a blast.

On the way up, a new noise started. It comes from the right rear. I thought someone here might be able to help analyze.

When I turn right, say driving onto an on-ramp, in first and second gear, the 1,500-2,500 rpm range seem to create this perfect resonance that causes a brief, 1 sec, "growling, throaty" vibration noise near the right rear wheel. I'm fairly convinced that it's not directly related to the drivetrain; that particular rpm range just causes the right vibration.

The keys to this:
1) Sound comes from the right rear.
2) Seems to only do it on right turns, when there is no weight on the right.
3) Seems to only do it when warmed up.

My suspicions:
1) Muffler? Could be that it would only do it when the muffler was warm. Could be a loose mount somewhere or something. The car has a SuperSprint on it that's been installed since I bought it.
2) Wheel bearing? I don't know enough about these but it seems conceivable. The car has been lowered at some point and has the camber out of whack in the back. Don't know if this might cause premature wear on a wheel bearing. Seems too inconsistent for this though, imho.
3) Shock mount? I know these upper shock mounts are prone to failure, but I did pull the right wheel and shake the shock at some point and it seems firmly attached.

Anyone have any ideas? If a wheel bearing seems likely, can I lift it up and pull on the wheel and get any telltale signs/sounds? When I lift and let down my car on a jack, the rear suspension seems to creak a bit, and this could be related. Car turned 100,000 on the trip. I'm at about 102,000 now.

Thanks in advance for any help anyone can provide!

[mrnine]

So...

The more research I do, the more I suspect a wheel bearing. I've looked through the TIS on this, but I'm having difficulty identifying a part number or a vendor online for these. Anyone help out here? Seems it's a 33 41 124 358, but I'm not sure. Can't match that up with anything on Pelican, and most other online sources don't stock wheel bearings. Is this a dealer only part?

Thanks!

[Jeff Spooner]

Snap-On makes a remote chassie ear for $500 that pinpoints the exact problem. I love mine. with out it they can be a little tricky. AUTOPARTSWORLD.COM has the bearings you need. they sell original supplier parts from the German manuf. Customer service is also some of the best of any online company. I would take it to a good BMW shop they can be very tricky to put in

[1996 328ti]

I think you would hear bad wheel bearings at all times, especially along a wall.
Could be RSMs. You can't tell by looking at them from the wheel wheel.

I knew I needs rear RSMs when I would make a tight turn. The rear would feel like it hopping.

Wheel bearings are not hard to find. My front wheel bearings came from WorldPac.

[mrnine]

I've posted this on BimmerForums as well and with a bit more detail. I agree, Steven, that it seems it would be more consistent. Here's my post from BF:

Name That Sound! - Wheel Bearing?

I have a 1998 318ti with a new sound. I believe it is likely a wheel bearing, but part of me is suspicious it's something else.

I can only describe it as a "throaty, growling" vibration from near the rear wheel. It only does it on a right turn; consistent with a wheel bearing. But only between say 2,400-2,600rpm. So in a typical turning acceleration, say merging on an on-ramp, I'll hear it occasionally and never for more than a half second or so.

If I drive wide circles in a parking lot, and keep rpm's at 2,500, I can keep it fairly consistent. But it almost seems more like metal vibrating, such as a shock mount, perhaps.

Anyone have any guesses? Is it indeed a wheel bearing?

Also...I first noticed this noise at the start of a road trip I just returned from. I've put around 3,000 miles on the car since first noticing it, and the sound is only slightly louder or more frequent if any at all. If that's any help.

Thanks!

[1996 328ti]

I can't hear real high pitches so I don't really know what a worn bearing sounds like.

One way to check if it is a bad bearing.
Jack up the car, put your hand on the strut and rotate the wheel. You may feel the bearing vibrations in your hand. If you still don't feel anything, remove the wheel and rotate the hub. Then I would go even further and remove the rotor and try again.

I say this because. . .
I suspected a bad front wheel bearing for over a year.
I had my local BMW dealer check it. No failure found.
I had a local independent. he thought I needed one but listened through a stethoscope. Did not need the bearing. At the same time they flushed my brake fluid because I was going to the track. The next day I did not like how my brakes felt. I went to my other independent on the way to the track to flush my brake fluid again. He told me my brakes were fine. I insisted on new brake fluid. But without me even asking about the bearings, he told be mine where shot. He removed the wheel and rotor. Spinning the hub was like turning an old combination lock. All I heard was crunch, crunch, crunch. The others did not hear it because the bearing was being loaded down with the wheel.

I still don't think it would make a throaty sound, but I could be wrong as I often am.

[motorsport]

I dont know about a bearing making a deep throaty noise, but i do know bearings are a simple fix. Is it a similar noise to when you downshift into too low of a gear?

[natebracing]

Ok, I know this my sound weird, but when was the last time you replaced your brakes? The only reason I ask is that I had the EXACT same noise from the rear of my 318ti and it was actually the brake caliper rubbing on the rim. The factory aluminum rims fit extremely close to the brake components on my car and if the pads are worn down the caliper can get close enough to rub. I realize that it sounds impossible, but when I checked it out, there were scrape marks on the rim. Just an idea...

[extremecarsny]

i have the rear wheel bearings bmw original pats for $ 62.00 plus shiping h look my web extremecarsny.com