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Help me diagnose this WAA-WAAA-WAAA noise..

31K views 143 replies 31 participants last post by  TerraPhantm 
#1 · (Edited)
Help me diagnose this WA-WA-WA noise..(SOLVED!)

Here's the deal, started hearing a noise goes "waaa-waaa-waaa-waaa" almost like there is a bubble in one of my tires and ever revolution it hits the pavement and makes subtle noise. Items of note:

Frequency of WAA-WAA-WAA gets faster with speed, but not with engine speed.

Just removed all four 18's from my car one by one and replaced them with my 17's. noise still there, although not as loud due to the thicker sidewalls on the 17's. (no idea why that matters here).

So it's not a tire or wheel issue.

I thought it may be a wheel bearing, but I watched a bunch of vids of bad wheel bearing noises and I do not get any of those. With the car jacked up, I can spin the wheels freely and the only sound I get is the occasional rotor scraping pad noise.

I do not get any feedback into the steering wheel from this noise. Stepping on the brakes does not make it worse, nor does it make it go away. Pads and rotors and brakes are 100% fine, all suspension is 100% tight up front.

Noise seems like it may be coming from the front right passenger side.

I am thinking possibly Guibo, so I will check that, but I checked that last year when re-fitting my exhaust and it looked great.

What the heck is this mystery noise and where is it coming from? It is not loud enough for me to record on video, so don't ask...

Starts to become audible around 30-40mph, gets increasingly faster as I go faster, and once I am on the highway I can't really hear it anymore. All windows must be up and radio off to hear this wierd vibrating noise.

WTF! it was not there before.. any ideas?
 
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#2 ·
Sounds like you are describing a wheel bearing. What I've experienced myself is that you can attenuate a bearing sound by taking a sweeping turn at speed...if it's rt. side bearing gone bad, a left hand sweep would make the waa-waa louder.

The bearing is built into the front hub, so the repair is easier than doing a rear wheel bearing.

You might want to bring along a passenger to listen on that side...and maybe confirm it's the front. It's not always easy to tell front from rear when driving.
 
#6 ·
cannot reproduce sound with car in driveway and revving engine..

Sorry...I'll try to type slower next time!

Trizz, also, you can't always hear wheel bearings by just spinning them...there's not much load on them then.

BTW, when I started to hear mine go bad...been brewing for a few months maybe...I called it a whoop whooping.

When I saw the race of the bearing, it was scored only imperceptibly...maybe 1 mm wide, .1 mm deep, and 5 mm long. I was actually quite surprised that the defect in bearing was so slight.

Also, I wonder if at speed, the grease loosens up enough inside to quiet things down...just like when our pulleys go bad...they begin to be bad only when cold, but eventually they make noise all the time.
good point about the bearing needing to be under load to hear the noise.. car is at 160K and I've driven her hard around the corners and already replaced the suspension twice, so it does make sense.. Also I thought that once you get to a higher speed, the rpm's of the wheel get so high and it's spinning so fast that the subtle noise may just go away due to the speed of the wheel bearing.. wierd thing is that it doesn't really matter if it's cold or warm (not that it's been even remotely cold lately though, UG).

Just checked Guibo and all rear drive shafts/diff and everything looks great and is tight.

Next up, i will try the Dmax method of a hard sweeping left hand turn and listen to see if the noise gets louder. Then I will repeat with a hard sweeping right hand turn and listen for the same things... thanks for the advice!
 
#5 ·
Sorry...I'll try to type slower next time!

Trizz, also, you can't always hear wheel bearings by just spinning them...there's not much load on them then.

BTW, when I started to hear mine go bad...been brewing for a few months maybe...I called it a whoop whooping.

When I saw the race of the bearing, it was scored only imperceptibly...maybe 1 mm wide, .1 mm deep, and 5 mm long. I was actually quite surprised that the defect in bearing was so slight.

Also, I wonder if at speed, the grease loosens up enough inside to quiet things down...just like when our pulleys go bad...they begin to be bad only when cold, but eventually they make noise all the time.
 
#7 · (Edited)
Wheel bearings are famous for noise in these cars along with drive shaft center support bearings and guibo. Also make sure the exhaust hangers are not compressed and the exhaust touching anything under the car.

You need to spend about $15 for one of these -

http://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM

You can easily compare side to side and most likely isolate your problem easily with a mechanics stethoscope. Wheel bearing are best tested under load, but with a stethoscope, usually under no load you can hear the coffee grinder noise when spinning the wheel while probing the hub with the end of the stethoscope.
 

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#8 ·
Wheel bearings are famous for noise in these cars along with drive shaft center support bearings and guibo. Also make sure the exhaust hangers are not compressed and the exhaust touching anything under the car.

You need to spend about $15 for one of these -

http://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM

You can easily compare side to sit and most likely isolate your problem easily with a mechanics stethoscope. Wheel bearing are best tested under load, but with a stethoscope, usually under no load you can hear the coffee grinder noise when spinning the wheel.
always wanted one of those, but that one looks like there is no way i could be in the cabin, with that thing out the window, pointed near the bearing whilst the wheel is spinning, so it doesn't get all sorts of tangled up, and actually put it in my ears to listen to..

no coffee grinder noise with no load from what I can tell, however since the pads slightly tough the rotors, i'd have to remove the calipers to really get a good listen to the bearings. Maybe that is what I will try next.. Or the sweeping turns as Doug mentioned.
 
#11 ·
Not tires, already swapped them all and noise is still there. My best bet is to remove both front calipers and then rotate the rotor to see if I hear any grinding inside the wheel bearing.. That will eliminate any of the pad/rotor rubbing that I was hearing.

Do not think it has to do with pads or rotors because it should be more noticeable when I step on the brake slightly and I should feel it through the steering wheel a little bit, and I get neither..
 
#13 ·
heres what you do to determine if its a wheel bearing (most of the time this works): jack up the car until the suspect wheel is about an inch off the ground then put a prybar between the wheel and the ground and pry the tire up towards the sky (carefully). if it moves at all or seems loose in any way you need a wheel bearing. if not keep hunting, hope this helps.
 
#15 · (Edited)
I can spin the wheels freely and the only sound I get is the occasional rotor scraping pad noise... any ideas?
That occasional pad/rotor scraping sound could explain your waa-waa noise. so could a kid in your back seat.

Edit: new to bmw, but most cars you can grease your front wheel bearings, and adjust preload. Can you do this on bmw? Your occasional rotor scraping could be due to slightly loose wheel bearings. Or rust on the rotors.
 
#16 ·
All E46/E39 and most other BMW wheel bearings are sealed units that do not have pre-load. They are caged units.

Brake noise likely to go away with light brake pedal application.

Could be exhaust touching part of the body or a cross member.

If the exhaust was modified and resonator removed, it could be exhaust drone.
 
#17 ·
mmmmmmmmm UUC TSE3 no drone :drool:

still think it might be the bearing, too f'n hot outside now to even want to go remove that caliper.
 
#18 ·
I am having the exact noise problem you are describing. Mine appears to be coming from the rear. Was told tire(s) at first and since the tires were getting close to the end of their time, I replaced those. Noise still there and has gotten a little louder recently. My local repair guys are now telling me its either one or both of the rear wheel bearings, but they cannot be sure which. Mine also makes no noise spinning freely on the lift. Makes sense that the noise would only be under load. Suggestion for me is to drive some more till it gets louder and they can be sure which side to replace.....or I could fork out the cash and do both sides. The stethescope idea is an interesting one.
 
#19 ·
yeah, stethoscope would probably help you identify which one it is before it gets worse..

I wonder if the stethoscope my parents gave my kids for their birthday would work? It is a legit MD steth.. but does not have the long probing rod, just has the normal steth bottom with the flat black circular diaphragm..
 
#20 ·
Add a section of hose to the end of stethoscope. I still love my 1" diameter flexible electrician's conduit...and being 5' long, allows me to get to places I otherwise couldn't.

Almost always with bearings, they go in pairs within a close period of time...unless you took a hard hit on one side or the other...in which case you'd have a bent wheel rim to show for it...and probably the same in the front.
 
#21 ·
To use the stethoscope to find the bearing, jack the car up and have someone spin the tire as fast as possible and put the stethoscope on the hub and listen. Usually best to listen to both sides as a comparison.
If the noise is suspected on a drive wheel (our rears) you lift the car and put it in drive to spin the tires up to 30ish mph, turn off traction control, and listen that way. Works better but you have to be sure that your jackstands are securely set.
 
#23 ·
i say wheel bearing. i have diagnosed many of them and the easiest way to do that is to drive and make sweeping s turns to load each side of the car. listen for the waa waa to get louder when you make a turn left turn indicates right wheel bearing and right turn indicates left wheel bearing. it will get louder as speed increases
 
#24 ·
OK, so I did the DMAX test with sweeping turns this morning. Wide sweeping left hand turn, noise was much less obvious, wide sweeping right hand turn, noise got louder. Sounds like it is my driver's side wheel bearing. Must remove caliper, spin rotor to be sure. So odd, because from the cabin, it totally sounds like it's the passenger front!
 
#30 ·
So to update this thread, I finally got a chance to take both front wheels off and inspect. Based on the wide sweeping turns I took, it appeared that it was the driver's side wheel bearing that was bad, but after taking that wheel off, that sh(t spun like butta. Almost went to inspect the driver's side rear, but then decided it HAD to be one of the fronts based on where I was hearing the noise from and feeling the waa waa waa vibration, so I did the passenger side front, and let me tell you, it spun like butta too, but i can hear the waa waa waa very quietly inside, so that's def the one that is bad. Got the SKF bearing from BMA parts, and other related parts from autohausaz.com as I needed a few other things too. Found out that Autozone loans out a torque wrench that goes up to 250Ft/Lbs so I won't have to buy that! Got 46mm socket from Northern Tool, everything should be here in a week or so.

Odd that the noise got louder when I took a wide sweeping RIGHT hand turn which puts more pressure on the driver's side wheel. But that bearing is fine. Can't complain I guess they've lasted 165K!
 
#31 · (Edited)
you need to check your rear wheel bearings also. you have been given advice on ways to check the wheel bearings, but you really should be certain. at this point im not convinced youve done enough to verify. I can't say enough how common it is for a DIYer to mis-diagnose which wheel bearing is actually bad. only good part of this is at 160K i'm sure both side could use to be replaced.
 
#32 ·
you need to check your rear wheel bearings also. you have been giving advice on ways to check the wheel bearings, but you really should be certain. at this point im not convinced youve done enough to verify. I can't say enough how common it is for a DIYer to mis-diagnose which wheel bearing is actually bad. only good part of this is at 160K i'm sure both side could use to be replaced.
Funny, you're the second one who told me they weren't convinced that I knew what I was doing when I diagnosed this. I have done 100% of the work on my car since she went off of her CPO warranty a looooong time ago, including everything you can possibly imagine. Trust me when I say this, it's the front passenger side wheel bearing that is bad. I'm not going to just go buy 4 new wheel bearings and replace them if they don't need replacing, maybe in my younger days I would consider it, but she's getting old enough now where other things need to be fixed/replaced and it's just not in my budget to replace things that are not obviously bad. Once I replace this one and that sound goes away (which it will), and in the process, I am replacing all pads on all rotors, I will carefully inspect the rear.

Now, perhaps you can offer some advice on how to check if the rears are bad, simply put the car in neutral (it's a manual tranny) and I should be able to freely spin the rear rotors, correct? By the way, the mech's stethoscope was no use in finding out what was wrong with the bearing because the sound is so faint when the car is not under load, and everything spins when the caliper is off, including the dust cap. I supposed I could have put the end of the stethoscope on a stationary part like a brake heat shield, or part of the brake carrier and listened, but it was very obvious to me that the bearing was bad due to the sound I was getting every single rpm.
 
#34 ·
the turn-in and turn-out to load the bearing on a turn is an old trick. mostly good for the fronts. a tighter turn to take load off a side is best, but you need to keep long to be able to hear(or not) it longer.
using an automotive stethoscope to hear what the bearing is doing when turning is another. put the steth prob on the center while spinning wheel(center cap removed) and it'll work.
there is also the lifting wheel off ground and rocking at postion 3 and 9 o'clock and also 12 and 6. but these can also show a bad control arm/tie rod. some say our inner and outter bearing races keep this from showing the signs but i have found it still does to an extent.
on the rears (i don't suggest without a lift) is to run the rear and listen. this is more for a professional and don't suggest for a novice.
 
#35 ·
Pumping this thread full of useful information:

I recently ordered the front passenger side wheel bearing from BMAParts.com. Part was listed as being manufactured by "SKF" on their webite. Bearing came in, had SKF box, and when I opened it up, it said "F.A.G. Germany" right there in the middle on the edge of the bearing. Awesome! part cost about $73 free shipping from them. So save yourself the aggravation from autozone and get the real deal for an incredible price from BMAParts.com!
 
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