Rumble from the rear

[B234R]

Well, for a year or so I´ve been hearing a noise that seems to come from the rear of my 1996 328i, at first it wasn´t serious and sounded like a helicopter rotor (I mean, not a constant noise, but a zwe-zwe-zwe). It increased with car´s speed, not rpm, noticeable from about 40 mph to 75 mph, when the noise seemed to get covered by air or road noise. The noise can be heared driving straight and cornering; I would say it´s louder turning right. But now the noise is a kind of constant rumble and really disturbing, and at highway speeds the car vibrates a bit when turning right.

I was convinced it was a wheel bearing, even I got a quote from my mechanic, but today he jacked up the car, grabbed every wheel trying to move then in every direction, and he says bearings seem fine... any idea? Thanks..

[MIKYZZ4]

Did your mechanic even bother to check the differential? Fluid level, condition?
Don't disregard that tires may also be the cause of noise-swap front to rear, if possible.

[Twistytee]

Your description sounds like a bad bearing. It's possible it's a failed CV joint on one of the rear axles but that's usually evident as more of a clicking noise. Also possible to get rotation noise from failing CV joint on rear of drive shaft. Have you checked your wheels for loose lug bolts? What type of wheels are you using (hub centric spacers or hub rings?)?

[B234R]

Did your mechanic even bother to check the differential? Fluid level, condition?
Don't disregard that tires may also be the cause of noise-swap front to rear, if possible.

No, he didn´t check differential fluid level, but next friday I´ll take my car to his workshop and we´ll check it.
Swapping tires was my first try but it didn´t improve.

Your description sounds like a bad bearing. It's possible it's a failed CV joint on one of the rear axles but that's usually evident as more of a clicking noise. Also possible to get rotation noise from failing CV joint on rear of drive shaft. Have you checked your wheels for loose lug bolts? What type of wheels are you using (hub centric spacers or hub rings?)?

There isn´t any clicking noise. My wheels are OEM "styling 30", and yesterday I checked the lug bolts. They were tight.

On friday we´ll make a more comprehensive check, I´ll tell the results here. Thanks!

[jmo69]

Subscribed, I've got what sounds like the same noise. I've changed the dif fluid, checked the trans fluid level, pulled the driveshaft to check the CSB. I even thought it was from slightly excess camber in the rear, but not. I've even considered taking out the poly RTABs figuring it was NVH. My local indie blamed the tires, but I put two different tire set ups from the wife's e46 on and there was no change.

[chrisshara]

Wheel bearing ? Check rear shock mounts (upper). ...Bad wheel bearings can be confused with tire noise. But there is a difference in the sound.

[chrisshara]

Did you bother to read the first post?

I guess I forgot to quote jmo69. I guess I was trying to help jmo69.

Also, just because a wheel bearing is not actually loose, does not mean it's not the cause of the noise.

OP sounds more like a bad tire or bent rim.

[jmo69]

I guess I forgot to quote jmo69. I guess I was trying to help jmo69.

Also, just because a wheel bearing is not actually loose, does not mean it's not the cause of the noise.

OP sounds more like a bad tire or bent rim.

I've had two different sets of tires and rims on with no change, and there's no difference in the sound when going around corners. I've replaced both front wheel bearings and left rear. Even pulled both rear calipers off and drove with them wired up and off of the rotors, still sounded the same. No heat shields rubbing either.

[jmo69]

THIS is the VERY reason why Threadjacking is frowned upon!!!

??? I've got the same symptoms as the OP, just adding what I've tried to help us both solve the problem.

[chrisshara]

THIS is the VERY reason why Threadjacking is frowned upon!!!

Tell me how he's threadjacking if he has the exact same symptoms and there is not comfirmed fix ? Stop being a little punk. It's boys like you who make men like me not want to come on here. Did you even bother to check my activity ? I'm hardly ever on here. Becuase I rarely need any help. But, I came on here and had some people help me. So I'm trying to help, and at the same time learn how things go on the forum and you're being a punk. If you're going to be a punk, at least be right.
.....HE'S NOT THREAD JACKING.... (peace)

[chrisshara]

I've had two different sets of tires and rims on with no change, and there's no difference in the sound when going around corners. I've replaced both front wheel bearings and left rear. Even pulled both rear calipers off and drove with them wired up and off of the rotors, still sounded the same. No heat shields rubbing either.

Jack up the rear.. ..spin the left rear wheel.. ...since you replaced the wheel bearing, it should not make any noise when you spin the left rear wheel by hand... ...now go to the right rear wheel and spin it and see if both the left rear wheel and the right rear wheel sound the same when you spin them. Front wheel bearings are not as common as rear wheel bearings for going bad on RWD BMW's. The rear wheels constantly have load on them from not only the weight of the vehicle but also acceleration and velocity. If the sounds of the left and right wheel bearings sound the same when you manually spin them, then I'd suggest checking the guibo and transmission mounts for any cracking deterioration; as well as the drive shaft U-joints.

[B234R]

Last friday I couldn´t take the car to the mechanic, surely this week.

This afternoon I jacked up the car and turned the rear wheels, this is how it sounds. And the wheels were like braked...I jacked up the front and did the same with a front wheel, it spinned a lot more.

[E36328Coupe]

Normally if you turn right and the sound gets louder when the bearing is under load it is the left bearing. However, it can be the right bearing if the inner race of the right bearing is at fault, but this is rarely the case.

If it alters under load when the car corners it's a wheel bearing.

[romg424]

Most likely it would be a failing wheel bearing . In my e36 vert . it almost sounded like diving on off road tires around 65 mph. the sound wasn't that noticeable . but try to see if it stop making the sound while turning or putting load on the bearing. It'll sound like woob woob woob *stop as you turn in * woob woob woob hahaha. one bearing will cost you around $200 from a shop and you can buy the part off ECS tuning for like $20 including shipping . I would not recommend doing the job yourself . even if you used a slide hammer there is a lip on the other side of the hub that would keep you from pulling the bearing race off . if it were to come out separately . Which is most likely to happen . It is a PITA .... I had to digrind mine out without digging to deep into the hub . grabbed a 2x4 and hammered it in most of the way . Till I could get the nut on the end of the Axel and tighten it down .

[jmo69]

Jack up the rear.. ..spin the left rear wheel.. ...since you replaced the wheel bearing, it should not make any noise when you spin the left rear wheel by hand... ...now go to the right rear wheel and spin it and see if both the left rear wheel and the right rear wheel sound the same when you spin them. Front wheel bearings are not as common as rear wheel bearings for going bad on RWD BMW's. The rear wheels constantly have load on them from not only the weight of the vehicle but also acceleration and velocity. If the sounds of the left and right wheel bearings sound the same when you manually spin them, then I'd suggest checking the guibo and transmission mounts for any cracking deterioration; as well as the drive shaft U-joints.

I've had the car on jack stands, spun the wheels with the tires on, off, rotors off, parking brake shoes off of what sounded like the offending wheel. I've run it in gear and listened to everything turning. The transmission mounts were new at 112k, 147K now, guibo is even newer. When I had the driveshaft off there was no apparent issue with the U-joint. My next attempt is going to be draining the dif again and trying some heavier gear oil, I've got some 80-140 from work.

one bearing will cost you around $200 from a shop

It was $325 around here more than 5 years ago.

[jmo69]

Last friday I couldn´t take the car to the mechanic, surely this week.

This afternoon I jacked up the car and turned the rear wheels, this is how it sounds. And the wheels were like braked...I jacked up the front and did the same with a front wheel, it spinned a lot more.

The right one definitely sounds worse, the left just sounds like the normal brake pad drag.

[B234R]

The right one definitely sounds worse, the left just sounds like the normal brake pad drag.

Curiously, when the noise started a year ago, it was louder when I turned right, so I blamed the left one...
My mechanic replaced a rear bearing in another E36 last week and has quoted me a very good price (about $120/each), so if I end changing both bearings, at least it won´t be too expensive.

Thanks!

[chrisshara]

From where I am, and what I am able to hear, it sounds to me like your backing plate is scraping against the rotor, as you spin the wheel. ....No need to remove the wheel. Just use a long screw driver to push the backing plate away from the brake rotor at about 6 to 8 different spots around the perimeter of the backing plate. The backing plate is the very thin stamped plate that is right behind the rotor. If that is not it... ...then I'd say either wheel bearings or the emergency brake shoes might be shot. Maybe a small pebble wedged in the brakes or brake rotor ? Little link below

https://www.youtube.com/watch?v=HR8UbHpBfmU

https://www.youtube.com/watch?v=aXHdKuPeo_I

[jmo69]

Put some 80w-140 conventional gear oil in the dif today but didn't have time to test drive it. Did find out that when you drain Redline Shockproof out of a warm dif, it comes out looking like Pepto Bismal but thinner.

[jmo69]

The 80w-140 didn't make a difference, spun the left front wheel and just has a little more brake drag than the right side and a sound like something in the tire.
Took the wheel off, there is something rolling around in the tire, sounds like part of a valve stem, but the tire hasn't been apart since it was new

[B234R]

Rear left wheel bearing replaced and problem solved. My mechanic did it at a good price, so I don´t complain.
He changed the diff oil, too (75w90), and it seems that a small "thump" that sometimes came from the back when changing gears has dissapeared, too.

Thanks everybody.

[MIKYZZ4]

Glad you found the culprit OP, thanks for posting.