XC90 engine humming/droneing noise

[big fuz]

2004 XC90 D5 (163) 135,000 Geartronic

I can only describe it as a drone ing noise (almost like wind noise) from the engine bay ONLY when accelerating. The moment I come off the pedal the noise disappears.` Noticeable at speeds above 25-30 mph. I have read through the forums but it seems there are noises from, altenator-turbo-split hoses-belts etc so hard to know where to start as I can't find a thread that has mentioned the drone I am getting. The pitch also stays the same no matter what the speed.
After getting a recent service, I noticed that the air filter housing is far from sealed and the mechanic told me that this was normal as they can go out of shape because of prising it open using a lever against the fuse box, repeatedly over the years. Not sure if relevant, but only mentioning it as this -to me- is the area the noise is coming from. . He said he checked the turbo hoses and all ok, (visually from above while I was with him)
Anyone else have similar noises, I think from the passenger side.

Thanks

[big fuz]

Just a little more info on this annoying issue, The noise starts at 30 ish and disappears around 50mph. I'm starting to worry if its the turbo, but my indie said that after 20 years in a Volvo main dealership, he has never replaced a turbo.

[bobdabuilda]

My money is on a wheel bearing.... I had the same problem btw and this is what it turned out to be.

[Tannaton]

That's a curious one - suggest to try to narrow it down you:

- Check that it is proportional to road speed, not engine speed; use the geartronic to drop and lock it into 3rd and 4th and repeat the test to see if you get the noise at exactly the same speed? If you do then it's transmission/final drive/wheel bearing related. Does the noise change when the torque converter locks up at 55 in 5th, 40 in 4th or 3 in 3rd?

- Unlikely but just check the rubber seal at the bottom of the steering column and that it is securely located into the bulkhead and the small bearing on the steering column itself - i.e. air tight.

[volvo for ever]

get your garage to drive in on wheel free ramp switch off the dtsc then get some one to drive it and listen for bearing noise ..is it tyre noise possibly ???

[Danielpsmith]

I have the exact same noise on my s60 d5 03 reg it is a whining noise only on acceleration mine started after I had a new drive shaft fitted it's never got any worse in 2 years since it has been changed had it looked at lots and they found nothing guessing it's the diff or gearbox or something like that but it's still annoying when I drive it

[big fuz]

I will check this out as I do think it disappears as soon as I go into 5th. Just can't understand how its accelerator pedal related which almost acts as the switch for the noise. Will let you know the outcome. Thanks

[big fuz]

Thanks volvo for ever, I did think bearing at first but would it only make a noise when accelerating as there is nothing at all when free wheeling. Thanks

[big fuz]

tried a test run Tannaton. It does seem road speed related, as I got her up to 30 ish (uphill) changed from 2nd - 3rd - 4th on geartronic, obviously at differing revs and the noise stayed the same with no volume or pitch change. I was ruling out wheel bearing as it disappears when I come off the accelerator pedal. Is there an overdrive in these cars, as when I took her on the motorway 55mph in 5th and then it seemed to go into overdrive/ drop the revs a little and the noise stopped. Not sure if the engine noise drowned it out or it just stopped. I just reminds me of wind noise howling through an open window. FYI I got the gearbox oil changed when my indie changed the transfer sleeve last month. (the noise was there before the sleeve and oil were replaced)

[Tannaton]

Originally Posted by big fuz

tried a test run Tannaton. It does seem road speed related, as I got her up to 30 ish (uphill) changed from 2nd - 3rd - 4th on geartronic, obviously at differing revs and the noise stayed the same with no volume or pitch change. I was ruling out wheel bearing as it disappears when I come off the accelerator pedal. Is there an overdrive in these cars, as when I took her on the motorway 55mph in 5th and then it seemed to go into overdrive/ drop the revs a little and the noise stopped. Not sure if the engine noise drowned it out or it just stopped. I just reminds me of wind noise howling through an open window. FYI I got the gearbox oil changed when my indie changed the transfer sleeve last month. (the noise was there before the sleeve and oil were replaced)

Ok - so it's sounds like it is something drivetrain related then.

There isn't an overdrive on these cars, the change in revs at 55 mph is the torque converter locking up (i.e. becoming solid like a clutch rather than a fluid coupling) - this is as expected. You will also get the same thing happening at 40mph in 4th gear and 30 mph in 3rd gear but only when you manually select them (i.e. geartronic mode).

- I would suggest an experienced ear might be the best way forward - it's difficult to suggest what to do next as it's not easy to disconnect or substitute drivetrain components.

- Check that the transfer box output flange (i.e. connection to the rear propshaft on the gearbox) is not catching on the steering rack heat shield. If it is then this could be your noise and 99% means your rear engine mount is knackered. Hopefully this link will work: https://www.google.co.uk/search?tbm=...oAtyaKiOnJM%3A (the photo is not an XC90 - you can see the flange and immediately below it the steering rack. On your car there will be a sodding great exhaust and catalyst there as well). Another tell tale sign is if the gearbox is very close to or touching the rubber stop on the subframe at the bottom.