Humming tune from rear NOT tyres!

[patomlin76]

Please can anyone help with any other suggestions other than wheel bearings for the loud humming sound coming from my estate rear? Thought tyres so replaced them with premium pirelli tyres today, absolutely zero difference.

Every garage so far has ruled out bearings but only by doing the spin and movement check. All I can think of now is to pay a garage to check rear brakes and visually inspect the bearings. It's like a loud wind tunnel noise, maybe bearings are drying up? Completely out of ideas so it'll have to be over to the specialist - I honestly thought it would be unevenly worn tyres!!! :(


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[DSG4ME]

Please can anyone help with any other suggestions other than wheel bearings for the loud humming sound coming from my estate rear? Thought tyres so replaced them with premium pirelli tyres today, absolutely zero difference.

Every garage so far has ruled out bearings but only by doing the spin and movement check. All I can think of now is to pay a garage to check rear brakes and visually inspect the bearings. It's like a loud wind tunnel noise, maybe bearings are drying up? Completely out of ideas so it'll have to be over to the specialist - I honestly thought it would be unevenly worn tyres!!! :(


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I trust you've done the test on the lift pump I suggested?

If so I would now be looking at the rear door panel fit and also the boot lid and the rear screen as it would appear to me you have a new gap somewhere that has become a bass trumpet.

[patomlin76]

Dsg - I'd forgotten about the lift pump but will remind the garage about this - they should be able to identify the sound. Not quite sure what the pump would sound like - more mechanical? as we're definitely talking about a humming resonating from the rear tyre area. I did sit in the back and all I could hear was coming from behind me in the wheel well area.

It is now booked in with a proper vw specialist for Thursday, he suggested that if tyres had made no difference then the wheel bearings may be drying up which would not be easy to tell on a simple spin test. However they are sealed units so you need to be pretty sure they need replacing!


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[DSG4ME]

Dsg - I'd forgotten about the lift pump but will remind the garage about this - they should be able to identify the sound. Not quite sure what the pump would sound like - more mechanical? as we're definitely talking about a humming resonating from the rear tyre area. I did sit in the back and all I could hear was coming from behind me in the wheel well area.

It is now booked in with a proper vw specialist for Thursday, he suggested that if tyres had made no difference then the wheel bearings may be drying up which would not be easy to tell on a simple spin test. However they are sealed units so you need to be pretty sure they need replacing!


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It sounds like an electric sub station on acid when it's going south, I used to notice it sitting in the driver seat and the vibe of it would give me earache within an hour

If you sat in the back is it possible you have a tired spring and the tyre is rubbing the arch when the rear is loaded.

[patomlin76]

No, after chatting with garage this aft and more accurately describing the sound as a 'howling' above 20, he did say if not the tyres it can only be a bearing, probably drying out and only showing itself as the sound under proper load (not on jacks).

Ok I'll have to pay for one or both rear sealed bearings but hopefully the end of the saga!!


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[Caxap]

Once things done, please do update what actually was causing resonating noise.

[DSG4ME]

No, after chatting with garage this aft and more accurately describing the sound as a 'howling' above 20, he did say if not the tyres it can only be a bearing, probably drying out and only showing itself as the sound under proper load (not on jacks).

Ok I'll have to pay for one or both rear sealed bearings but hopefully the end of the saga!!


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One more thing Pat, you do know that on a car sound travels, so whats reporting from under the bonnet can actually seem like it's coming from the rear, another thought I've just had says it sounds like a plasticised label in the wind that is becoming a flag effect as the speed of the car increases, much like we used to clip playing cards to bike wheel spokes to get a motorbike sound from them (I know things kids come up with) but all it will take is a label that is able to foul a moving part or it simply becomes rigid in the wind to make a drone sound, maybe if you stick the car on a rolling road you may be able to hear it perhaps.


p.s, engine shield, have you recently had an oil change? you should check that all the bolts are there and that the shield has been refitted correctly, and one final one you could be getting this from a CVJ or a worn layshaft bearing in the gearbox.

To help you a bit more do this, inflate and deflate the rear tyres to 38 and 25 *at different times* and see if the noise changes note, if it does that should indicate the tyre compound or the bearing, with a CVJ you should be able to feel it through the steering and also the car may feel like the front is wiggling side to side slightly like a buckled wheel.

[patomlin76]

I need to stop reading these forums! Start worrying more about what it could be rather than what it is likely to be!

Firstly, it's not speed related as in it will always increase noise with speed - around 20-30mph when general tyre noise is quiet, that is when it is most noticeable, and also present at speeds you would not get wind noise.

Yes I have replaced oil recently and will again double check engine shield, again don't think it is this because although sound can travel at speed, it wouldn't be so prevalent from the rear at very low speeds unless it WAS at the rear. If the sound was only at 50-70 I'd understand in that time sound could shift front-back.

I've had enough getting my hands dirty checking tyres and everything under the car, just got to trust the professionals to sort it out. I can't leave it to chance if they think it's a bearing - got a 350 mile trip to Cornwall at the end of the month!

[patomlin76]

The car has today been thoroughly checked over and road tested by three different mechanics.

The wheel bearings are fine all round. The sound seems to come from the rear wheels in the drivers seat, however in the rear you just get general tyre noise.

They have suggested that because the sound is more noticeable towards the top of the car (i.e. raise yourself in the driver seat and it's louder) that it is more than probable it is from the roof rails swirling wind. So that I don't waste money with them trying to find the source, they suggested I take some tape and start covering sections/joins to bodywork to see what can reduce the noise.

Annoying though it is, more importantly mechanically the car is sound (and this coming from a trusted and completely 'independent from warranty' garage).

Sorry I have nothing more exciting to report!

edit: thought I'd add that I had noticed that volume increased the higher you positioned your head, but didn't link that with any wind noise from the roof of the car...

[DSG4ME]

The more you say the more this sounds like a noisy lift pump,

Try this, run the tank down to the red and park the car so the passenger side is in the gutter, tilt the car using the camber in other words, now listen on idle if you can hear a deep humming, also get your ear down on the back seat and listen for a whirr, if it's there it's ok if it's more like a heavy buzz it's likely the pump although working is on it's way out, you must have low fuel or it will muffle it.

[patomlin76]

Dsg, just so happens I am nearly down to empty so can do this check tomorrow. Would the pump make such a racket when on the move, such as what I am hearing?

Failing this ill be in the unenviable position of trying to source a wind issue which manifests itself at just 20mph!


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[DSG4ME]

Dsg, just so happens I am nearly down to empty so can do this check tomorrow. Would the pump make such a racket when on the move, such as what I am hearing?

Failing this ill be in the unenviable position of trying to source a wind issue which manifests itself at just 20mph!


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Possibly, although mine used to get masked by the road noise tbh, it was when I was sat idle I used to hear it but it made such a frequency it used to make my ears buzz by the end of a shift.

[patomlin76]

Cheers, checked out as per your guide, all seems fine. Looks like I'm on the hunt for some wind resistance...


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[patomlin76]

Update:

Wind noise did not make sense with VW (took it to a main dealer who got a technician to test drive it for me), you wouldn't get intrusive wind noise in a car at 10mph at the depth we were hearing.

They suspected a wheel bearing starting to wear but admitted they had heard much worse.

Took it to a mates garage (for mates rates) and they definitely say bearing, but which one they don't know. When it's booked in next week they will strip the rear pads and spin the wheels without the friction of the brakes, they think they've already identified the near-side rear.

It's all making more sense now because 4 weeks ago I didn't have any noise at all, and it's gradually got worse that it's there at 10mph and very loud at 30-40mph. Unfortunately I can't get the work done before my trip to Cornwall this weekend but I've been advised that whilst annoying, it is not yet dangerous.

Thanks...

[zollaf]

not dangerous unless it does happen to collapse, lock up and your wheel falls off. yes, this did happen to me once after i ignored the warning signs.
thats an awful long way to go on something thats a ticking timebomb.

[patomlin76]

Zollaf, that post was enough for me to argue with Toyota that they'd missed them first time round, VW and another have both noticed it, so a 'forceful' call later and they've got it tomorrow.

Thanks !!


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[patomlin76]

Quick update!

Both Toyota and a local specialist had the car on the same day before we went on holiday and both said it must be normal traits of the car. I argued back that it most certainly wasnt - if it sounded like this on a test drive I would have walked away. Toyota also claimed that because there was no noise whilst spinning and no wobble, then they would not be able to do a replacement under warranty as it was still 'functional'.

As a result I'm getting the rear bearings properly tested (i.e. rear brakes stripped off to isolate any noise) and then replaced. The local garage near me have been very good - they immediately heard the hollow hum on a test drive and suspected bearings on one side, as the tyres were brand new (also a sawtooth sound is more like a rumble). Funnily enough, every other garage that has tested the bearings have just done the simple spin and wobble check. It seems obvious to me that you really need the friction of the rear pads out of the way first!

I think this will sort it given the characteristics of the humming sound but regardless I can't see any other option - (especially given the mates rates I've been given for them to be replaced) - It's not tyres, it's not wind noise, it's not the lift pump. I'm now just paying to get it sorted myself!

[Teflon]

I won't re-post the entire strory, but I've just experienced something similar and cured it. Maybe yours is the something simliar? Wierd Tyre Noise - here's a puzzler (http://www.vwaudiforum.co.uk/forum/showthread.php?147274-Wierd-Tyre-Noise-here-s-a-puzzler&p=820111#post820111)

[patomlin76]

Thanks Teflon, I read your post but guess mine is even more of a puzzler than yours!

Because it's not rumbling. It's a hum. Definitely!

As it is always present, though louder on rougher roads, I am thinking that it may well be the bearings, but at such an early stage that no inspection nor spinning of wheels can prove.

It has new quiet Dunlops on the rear and Pirellis on the front, all brand new. So it definitely isn't saw-tooth wear!

Think someone blowing over an empty wine bottle or something - deep hum from 10mph upwards.

Nothing else has changed with the car externally so it can really only be from the rear wheel assembly. If it were only happening at higher speeds I'd agree that sounds can travel, but doubt they can travel so convincingly at a low speed.

I'm now resigned to living with it for a few weeks and waiting for it to get worse, that will force the warranty company to replace them!

Now this is a puzzle!!!

Paul

[Gaz_burns]

Mate, I have exactly the same issue with my golf 1.6 TDI. Been chasing it for a year now. Had it checked by Indy garage and rotated tyres, no better. Trying to find a garage with an electronic chassis ear that would allow us to pinpoint the exact source of the noise, but have so far no located one

[RichardSEL]

Mate, I have exactly the same issue with my golf 1.6 TDI. Been chasing it for a year now. Had it checked by Indy garage and rotated tyres, no better. Trying to find a garage with an electronic chassis ear that would allow us to pinpoint the exact source of the noise, but have so far no located one

When I had noise sounding like wheel bearing had a four wheel laser alighnment done, and it went.
Also noticed that when I upped the tyre pressures from standard by about 5 psi, then the noise came in (and out)
at a different speed

[Gaz_burns]

When I had noise sounding like wheel bearing had a four wheel laser alighnment done, and it went.
Also noticed that when I upped the tyre pressures from standard by about 5 psi, then the noise came in (and out)
at a different speed


Well I was considering that. It came Supplied with the Hankook Ventus (something or other) and the front two had unusual wear. Had it to an Indy for Servicing who noticed this but checked the alignment on the front two wheels and it was spot on. Have rotated the tyres and the noise is still prevalent, if not even louder, and Im sure still from the rear, but no so much from the right hand side of the car. Problem is the noise oscillates so you can never be sure where its coming from, but you can hear it at speads as low as 15-20mph.

the only time it completely goes is on the motorway if you go from normal asphalt to smooth freshly laid asphalt. This is pretty rare. As soon as you are off the motorway and driving slow speeds its pretty much there all the times. Sounds like the vibration of the tyres on the road beings transferred to the springs.

[RichardSEL]

I've got 16" P6000 all round and have just done front to backs on this estate.
Now the rumble comes in at about 15 and goes again at about 25mph. Before
it was 30 and gone at 40. That was more annoying.

Used a Hunter-equipped outfit at Rainham. Static tracking just won't cut it
In this dry weather try upping the psi. And if no change then the laser track?

Should've added that I've only got about 3-4mm tread left on these P6000s so
due MOT in Nov and will change then

Let us know how you get on? Good luck!

[patomlin76]

Well I was considering that. It came Supplied with the Hankook Ventus (something or other) and the front two had unusual wear. Had it to an Indy for Servicing who noticed this but checked the alignment on the front two wheels and it was spot on. Have rotated the tyres and the noise is still prevalent, if not even louder, and Im sure still from the rear, but no so much from the right hand side of the car. Problem is the noise oscillates so you can never be sure where its coming from, but you can hear it at speads as low as 15-20mph.

the only time it completely goes is on the motorway if you go from normal asphalt to smooth freshly laid asphalt. This is pretty rare. As soon as you are off the motorway and driving slow speeds its pretty much there all the times. Sounds like the vibration of the tyres on the road beings transferred to the springs.

Gaz

You have completely described my situation too, and even more puzzling is that when it was look at by a garage who drove it with three mechanics, they said that when they were in the back they couldnt fathom where it was coming from - so to me it sounds like general tyre noise that I hear in other cars, only 20 times worse!!!! The din is ear-splitting on rough roads even at 20mph.

I'm very interested in RichardSEL suggestion that the hunter alignment sorted it out. I do know that places with hunter machines will test your machine and give you a read-out for free, then only charge when making the adjustments. It may be worth looking into this as I have been told it is not bearings as a) it is not a typical bearing sound, and b) changes depending on road surface – but is always there, just at different volumes.

Gaz can you confirm this is exactly what you're experiencing too. Maybe there's a solution around the corner, but I thought that two months ago! I know it's not wind-noise as that wouldn't changing dependent on surface. I'm also happy I'm not the only one as I was led to believe by many garages that this sound was perfectly normal (!!!!!???!)

[zollaf]

just had a customers car in with a similar noise, its an 04 a4 1.9tdi. traced that to a front wheeel bearing. when you spin the wheel its not noisy, until you spin the other (new bearing in that 4 months ago). its just slightly noisy but the other side is silent. bearings can be a pain to detect and be sure about, but if its not a tyre or bearing, theres not much else it can be.

[RichardSEL]

Sheesh! Just realised these P6000 have done 27,000m Don't think that invalidates my previous advice though: 3-4mm on each left,
although NSF is a bit rounded, down to 2mm outer edge (now on NSR)

[patomlin76]

just had a customers car in with a similar noise, its an 04 a4 1.9tdi. traced that to a front wheeel bearing. when you spin the wheel its not noisy, until you spin the other (new bearing in that 4 months ago). its just slightly noisy but the other side is silent. bearings can be a pain to detect and be sure about, but if its not a tyre or bearing, theres not much else it can be.

Thanks Zollaf...

Thought I'd add that yesterday I did a very basic test on my own - iphone video set in the car, and I jacked up and spun as fast as I could (aided by tube in spokes) the wheels of each corner. Playing the videos back, the tell-tale hum *seemed* to appear only when spinning the front offside wheel.

Is it possible that this sound could travel to make it appear more central in the cabin? It would explain why no sound out of the ordinary can be heard from the rear seats...

Finally, what's the best way to test this properly - front wheels on a rolling road (for load bearing weight) or jacked up and driven in gear?

Cheers


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[zollaf]

i have known rear bearings sound like fronts, fronts sound like rears and other noises go all over the place. think of a car as a large steel box, very good at sound resonance. now, if a bearing is slightly noises when spun by hand you can bet your life its really noisy on the go. just done one on an a4, not really noisy but noisier than the new one the other side.

[DSG4ME]

In that case start looking at CVJ's Pat,

The inboard kerbside one is one that splits it's boot easy.

[RichardSEL]

Is that because the circlip's done up too tight?
Had my NSF boot go, it was a clean cut right by the outerside of the circlip

That was two year's ago, some numpty replaced it with a universal boot coz he
didn't know how to (was nervous of) dropping driveshaft and could'nt get proper
boot over knuckle.
A few weeks later had MOT and it'd perforated. Just an advisory.
One year later had it changed for a proper part, done properly, and had MOT, all OK

Just had this year's MOT and still fine, installer (Volks Autos) used a rounded
edge circlip = Proper job

[patomlin76]

There is no clicking sound when turning and the sound doesn't sound like a cv joint at all - spinning wheel when car stationary tends to point towards a hub issue. Will keep you updated on progress!


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[RichardSEL]

There is no clicking sound when turning and the sound doesn't sound like a cv joint at all - spinning wheel when car stationary tends to point towards a hub issue. Will keep you updated on progress!


After a run, is there any extra heat felt, or with thermometer measured, on one wheel hub or disk as compared to the others?