How to identify wheel bearing noise?

[PranK]

So the X5 has recently started making a whirring noise in the front. Volume of the noise is related to road speed, not revs. We just discovered today that it goes away when going up a hill and is back when on the flat or going down a hill.

That makes me think it could be bearings as there would be less weight on the front when climbing. Does that sound sane?

We will take it in for an opinion from my BMW guy on Thursday but in the meantime just trying to work it out.

We did try to load up each front side at 70ish kph by doing a bit of a slalom. I did hear that you can isolate each wheel this way but we heard no difference from each side. 

I'm just hoping its the bearings and not the front diff or something else. Not after what I just spent on the E90!

[GTSBoy]

10 minutes ago, PranK said:

less weight on the front when climbing. Does that sound sane?

Maybe, but the % change is actually pretty small.

[PranK]

7 minutes ago, GTSBoy said:

Maybe, but the % change is actually pretty small.

So I'm not a genius? Is that what you're saying?

What else would change in volume based on climbing or descending ?

[GTSBoy]

It's a Euro debt trap, so....just about anything? Cam drive, flux capacitor, money pump, etc.

[PranK]

3 minutes ago, GTSBoy said:

It's a Euro debt trap, so....just about anything? Cam drive, flux capacitor, money pump, etc.

Money pump was done recently. So, it must be that.

[PranK]

Ok, bumping this because I still need help. 

Front and rear diff fluid done and gearbox service with new pan/filter. 

Noise is still there. It's only happening under load which is why my wife thought it was not happening when going up hills. 

The front tyres are wearing strangely (mainly outside edge) but there's no lumps or mounds in the tyres. 

Could this still be wheel bearing if the noise is conditional to the load? Maybe under load it lifts the front a little? Maybe I'll get it on the jack and see if there's any play there. 

Thanks guys.

[niZmO_Man]

A euro that old, I'd change the bearings anyway. But definitely lift the wheel and give it a wobble.

[PranK]

I just spent a silly amount of time reading other forums' posts and watching "whats this noise" videos on Youtube.

It *appears* to be the front diff having killed a pinion bearing or similar. Its almost definitely driveline, I haven't tested to see if the car makes the noise in N though but either way I think it's gonna be pricey. This is outside my area of comfort and expertise so I'll get my BMW guys on it.

The bearings are attached to the hubs so are super easy to replace (at least in comparison to press in bearings) so I'll do them also. 

[PranK]

Diff. Confirmed today.

$5200 from BMW. 🤣

$2200 for a used one.

$1000 for a refurbished one from China. 

[niZmO_Man]

Man... good luck. Let us know how it goes (since my car is getting 10 years old soon).