Drone at speed... suggestions needed

[2Btoo]

Guys,


My 2007 (57 plate) Skoda Fabia has started to make a droning noise at speed. It's definitely road speed related and becomes audible at around 35mph or so, getting louder as faster as you go faster. It still makes the noise when coasting out of gear (and when coasting with the engine off.) It started earlier on this week and has become worse quite quickly in the last 50 miles or so. It's a (very) basic 1.2l model with a 5-speed gearbox and FWD.

I've just serviced it and can't see anything wrong. There was a hole in a CV gaiter which was weeping grease so I took it apart, cleaned the CV out and re-packed it with grease and re-assembled with a new gaiter. All the wheel bearings seem fine; the rear wheels spin with no noise, the front ones spin as best they can given that they are attached to the gearbox and there is no apparent play in the bearings. The gearbox oil level was down quite a lot so I topped it up but that's made no difference.

The car drives absolutely fine, apart from the noise. The noise doesn't seem to come from any corner in particular (it could be front but I'm not sure.) It doesn't get worse or better when going 'round a corner in either direction. It happens regardless of what the engine is doing, and regardless of whether you are on power (i.e driving the wheels 'round) or coasting. It's a drone, not a clicking such as I'd expect from a dying CV joint.

Does anyone have any suggestions as to what else it could be apart from wheel bearings? I guess my next step is to replace them to see if that makes a difference, but I'd rather diagnose the problem properly and only replace the parts that are needed.



Thanks.

[E-bmw]

Could just as easily be tyres, what condition/age are they?

Check the pressures all round, and look for any weird wear patterns.

[tux850]

2Btoo said:

and when coasting with the engine off.

Whoa! If that involved turning the ignition key to Off just be mindful of the risk of the steering lock engaging!

Back to the problem in hand, it sounds like you've been fairly thorough in attempting to pinpoint the cause. I started to wonder about it being tyre related but would expect different road surfaces to become relevant in that case - any obvious variations there?

Rather than speculatively replacing any parts I think I'd be inclined to wait until it gets worse and, hopefully, becomes easier to pin down as to what the cause is. My money is on wheel bearings, and certainly I've had a couple that have been hard to diagnose in any other way than actually driving. Additional passengers can sometimes help pinpoint the offending corner given the increased load.

[TwinKam]

E-bmw said:

Could just as easily be tyres, what condition/age are they?

Check the pressures all round, and look for any weird wear patterns.

It will almost certainly be this, pass the palms of your hands around the tread, you'll know it when you feel it, the edges of the blocks will 'pick' at your skin rather than smoothly slide by, and the tyre may not even feel round, but faceted like a 50p piece.

Edited by TwinKam on Friday 7th July 14:02

[lufbramatt]

Agree with tyre wear issue- one of my mates had a similar age Fabia that had a drone at speed. Was “sawtooth” wear on the rear tyre tread.

[ARHarh]

Wheel bearing issues can be trickey to locate, often there is no play and little noise when not under load, e.g. up in the air being spun by hand. Best way to tell is if the noise changes when cornering, if it does its almost certainly a bearing and will become easier to spot as it wears more. Which bearing then is the difficult bit.

[2Btoo]

Guys,

Thanks for the answers. They are all helpful.

tux850 said:

Whoa! If that involved turning the ignition key to Off just be mindful of the risk of the steering lock engaging!

Rather than speculatively replacing any parts I think I'd be inclined to wait until it gets worse and, hopefully, becomes easier to pin down as to what the cause is. My money is on wheel bearings, and certainly I've had a couple that have been hard to diagnose in any other way than actually driving. Additional passengers can sometimes help pinpoint the offending corner given the increased load.

Thanks for the warning Tux, and the suggestion of waiting until it gets worse! It's very hard to pinpoint at the moment so bringing in some passengers is not a bad idea.

TwinKam and lufbramatt, thanks. Tyre noise is one thing that had occured to me. They are 18-month-old Yokos, with about 12,000 miles on them. So neither old nor worn, and I rotated them at the service a couple of days ago and there was no change in noise. However I'll certainly run my hands over them to see if there is wear such as you suggest. What causes such a problem to occur - i.e. why do tyres wear like this?

ARHarh, thanks. There are no clues from cornering; a sweeping left-hander makes no perceptible change to the noise and neither does a sweeping right-hander. ('Sweeping' because you need to be doing 40+MPH to get the noise to manifest itself, so a bit quicker than you'd get in a car park or similar).

I'll keep you posted. Thanks for the suggestions.

[GreenV8S]

I think that wheel bearings/tyes are the most likely causes, but don't rule out mechanical resonance or aerodynamic flapping as possible alternative causes. Unfortunately the only way you're likely to locate those is by putting your hand on the offending part.

[tommytaylor]

Best way to check a wheel bearing, jack it up, grab the spring and spin the wheel, any vibration will be felt through the spring.

[finlo]

We sent our new ioniq back to have the wheel bearings checked because of the awful droning but nothing untoward found put up with it for a couple of years before binning the perfectly good Michelin's, voilà problem solved.

[2Btoo]

Guys,

Thanks for the answers. Problem now solved.

New bearings procured from Parts in Motion (who are excellent), fitting tool bought from Amazon. This one, should anyone be interested:

https://www.amazon.co.uk/gp/product/B07QPYYS9W/ref...

Old bearing came out very easily with the tool but putting the new one in was a pain in the neck; it wouldn't go straight with the puller and needed to be tapped straight with a hammer and small drift several times in the process of pulling it in. Other than that the job was easy enough (even the ABS sensor came out very easily!) and having driven the car the noise has gone. There are several other speed-related noises which I heard but that's with a very critical listen and I suspect they are quite normal (it's my wife's car and I don't drive it regularly.)

Thanks very much for your help chaps. FWIW, this was the definitive test to identify that it was indeed a bearing, and which corner it was:

tommytaylor said:

Best way to check a wheel bearing, jack it up, grab the spring and spin the wheel, any vibration will be felt through the spring.

Thanks Tommy.

Should anyone in the Cheltenham/Gloucester area want to borrow the tool they'd be welcome to ; it's clearly something that only does one job so it will now sit on my self gathering dust for the next 40 years!