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.