Rumbling sound.

[benjie]

My Car has developed a rumbling today, does anyone have any suggestions as to what it could be? I was driving earlier and heard the rumble at about 55-60 and about 45-50. I actually thought it was the exhaust of the car ahead. But then it got worse and it happens all the time now, almost like I have a moped stuck under the car. Minimal vibration from the pedals, none through the wheel. Rumbling tone is constant & doesn't change with revs or if put in neutral. I have checked each tyre for the correct pressure & made sure the wheel bolts are done up properly. Car is an 09 and has done 65k miles.
Any ideas?


I got some new tyres fitted on Thursday and have driven about 200miles on them so far, not sure if it's relevant but worth mentioning.

 

[kanecullen89]

Is it a noise from the front or rear?

Could be wheel bearing or rear diff (if quattro) but these are guesses without more info. Could be a balancing issue or a defect with one of the tyres (bulging)

 

[mrose]

Have a look underneath, could be exhaust bracket loosened or cracked. Actually it could be a lot of things. Have you had the spare wheel out recently? Put back properly and screwed down? I had a heavy rumble once and it was the spare loose and rattling in the mount.

 

[benjie]

Thanks guys, I've not had the spare out, but checked and it's in nice and snug, tyres have no bulges and seem ok.

I'm thinking bearing but can't tell if it's coming from the front or back. I'm currently leaning towards wheel bearings, but can they 'go' in such a short distance (no sound to constant in about 40 miles)? I do have quattro and the sports rear diff, so I would hope that that would give me a warning light on the dash if that was giving up the ghost.

 

[kanecullen89]

I'd be swinging towards wheel bearing but there's so much things to make noise. Could be something simple like a heat guard come loose (on mine a rear heat guard near the exhaust and driveshaft at the rear rattles over bumps because it's corroded and cannot be secured properly anymore)

Could be a stone stuck in the carriers or near the disk? I've heard of that causing noise issues (mainly on the a3 platform but could affect ours too).

My car doesn't have a sports diff, just a standard rear diff so it may be different on yours but normal rear diffs aren't connected to the electrics at all so you would never know if there's an error. I don't think it would be the diff though, I think they're pretty strong. You've only done low miles too but if you figure out that the noise is the rear diff then would be worth an oil change to see if that resolves it

 

[benjie]

The sports diff has a sensor and control unit I think Kane, but thanks for the suggestions - I'll go out in the morning and have a good look underneath. I was under there on. Monday so will hopefully notice something out of place.
I'll have to get it booked in ASAP on. Monday when the garages open again (note that the car did this just as garages were closing for the weekend!)

 

[mrose]

Thanks guys, I've not had the spare out, but checked and it's in nice and snug, tyres have no bulges and seem ok.

I'm thinking bearing but can't tell if it's coming from the front or back. I'm currently leaning towards wheel bearings, but can they 'go' in such a short distance (no sound to constant in about 40 miles)? I do have quattro and the sports rear diff, so I would hope that that would give me a warning light on the dash if that was giving up the ghost.

Did you have any other work done other than the tyres? Just another thought, have a look at anything that might have been removed and refitted recently such as the under panels - if they loosen you get a horrible rumble as do engine covers, wishbones, flopping wheel arch liners and that type of thing. You'd be surprised how often clips are broken, screws lost, or threads stripped during servicing and the culprit has thought 'that'll do, they'll never notice'. The key characteristic is it's constant and doesn't change pitch with revs or if you're in neutral so I'm thinking something static but loose rather than something drive train related. If it was sharp or grinding and metallic I'd be thinking brakes, discs or disc guards.

 

[Spares]

Hey Benjie, I notice from another thread that you recently fitted a solid infil into the void bush on your gearbox, it might be wise to check you've not damaged your gearbox or the mounting as filling a void bush is not a good thing to do, as that movement has to go somewhere and if it can't it can easily fracture the castings.
Otherwise, check you've not got a loose wheel, if you've just had new tyres fitted it's possible one or more haven't been torqued up properly and come loose.

 

[Zafi]

Front wheel bearings last around 60,000 miles on an A4, so yours is bang on time for a set of two. Not worth swapping just one side.

Cost about £110 a side for the bearing/carrier assembly.

You can buy just the bearing from a factor, but its easier to fit the assembly.

 

[opelfruit]

and yes a bearing can go that quickly. I had one go on a previous car in the space of 3 or 4 days, from no noise to gone. When I changed it the entire thing had pretty much disintergrated not pretty, or worth the bill if I had left it.

 

[Jay.Ing]

Ive heard tyres that can make you think its a wheel bearing, a mate had a MX5 with some michelins and these sounded like a duff wheel bearing around 50 mph! Don't want you to go changing wheel bearings if its just the tyres you've had changed!

 

[johnnythepie]

I would do a front to back swap with the wheels to eliminate a tyre issue seeing as this has started after fitment .I have had a duff new tyre before that caused a similar sound similar to jay's post

 

[benjie]

Thanks for the extra info guys, I appreciate your help and input.
Spares - it was the first thing I removed, no change
Jay/Johnny - I wondered about tyres too, I've only a few hundred miles in them. Do you think the rumbling would have been immediate with them though? I'll swap the wheels over later though to elimate them.
Going to get it booked in ASAP just to make sure and not drive till then, as I don't want it to be the bearings and have them fall apart as opelfruit says!

 

[jaygemson]

Mine has the sports diff too and rumbles noticably during tight turns, smooth as silk otherwise though.

Mine's weeping slightly on the driver's side driveshaft seal. I was told by Audi not to worry about it, but that if it becomes bad enough to cause droplets on the floor to get it booked in. There's a TSB for that issue I believe. My point being that if yours has been weeping/leaking slightly for 65k then it may be low on diff oil.

 

[benjie]

Garage called today, n/s/f bearing. I'll admit to being slightly stressed thinking "Did I buy a lemon?" But all now is well.

I asked them to check the drive shaft seal, as Jay mentioned, and he said it all looked fine.

Thanks to you all for your help and knowledge!

 

[mrose]

Garage called today, n/s/f bearing. I'll admit to being slightly stressed thinking "Did I buy a lemon?" But all now is well.

I asked them to check the drive shaft seal, as Jay mentioned, and he said it all looked fine.

Thanks to you all for your help and knowledge!

Glad it's sorted mate. You didn't buy a lemon but you are driving a nice car on some of the worst roads in Europe, your wheels get a right battering these days.

 

[jaygemson]

Great news! Nice catch by those suggesting wheel bearings.

 

[Zafi]

Ask them to change both sides, it will only be a couple of thousand miles until the next one goes and it will cost more to get them done separately... and more inconvenient to you.

 

[rum4mo]

Ask them to change both sides, it will only be a couple of thousand miles until the next one goes and it will cost more to get them done separately... and more inconvenient to you.

+1 also, if they then insist on carrying out an alignment check, it will really hurt if you need to pay for that again in a few 1,000 miles time. (VW did that on my old B5 Passat V6 4Motion)

 

[vw754]

funnily my b8 does similar..........i get a rumble from the front of the car,it starts off faint at around 15mph then can hear it just like a wheel bearing at 26-30mph,then at 35mph it fades out and dissappears,then no more rumble..........only getting at low speed as mentioned,had m.o.t done,tester said theres no play,or rumble when spinning any of the hubs by hand but...obviously he cant spin the hubs at 15+ mph..........all 4 tyres have around 6mm(federal evo 255 35 19) these were fitted when i got the car last year,with the noise...........dont know what to do,dont want replace wheel bearings and still have the issue........ took front wheels/tyres off put em on the back.....still got the rumble..........any ideas how to check bearings as the noise only starts off at 15mph?

 

[benjie]

I had both changed.

vw754... My garage (VW/Audi specialist I have been using for ages) said that he couldn't find any evidence of the bearing going until he attached a bit of kit he had. Can't remember what he said it was called, but it sounded like attaching a microphone on each wheel, then going for a drive and listening to the input from each wheel to get a better idea about what's going on at each corner.

 

[vw754]

Wow ! didnt know stuff like that was available.........shame no one in stoke on trent has this. I usually fit everything myself,but dont want guess and start putting bearings in,knowing my luck it'd be the 4th bearing i replace !

I had both changed.

vw754... My garage (VW/Audi specialist I have been using for ages) said that he couldn't find any evidence of the bearing going until he attached a bit of kit he had. Can't remember what he said it was called, but it sounded like attaching a microphone on each wheel, then going for a drive and listening to the input from each wheel to get a better idea about what's going on at each corner.