Differential

[Addle66]

Good afternoon guys... Newbie here after a recent purchase of a 2.5 2011 Z4.

I have been looking for a while for a good z4 and found one in Surrey with only 22K on the clock.

Drove it home - really happy but could hear a whine from the rear inside the cabin.

Off I went to two main dealers who diagnosed the noise as coming from the rear differential. After a great deal of deliberation, and deciding that the car was worth the investment, I ordered and had a new differential fitted.

Went to collect the car and drove it home... B*gger me.... the noise is still there when the engine is idling... I should have thought about it... hindsight is a wonderful thing. If the noise was there when idling, then it cant be the differential as it is not operational.

I'm guessing now its the fuel pump.

Next, on the way home the engine light came on, so off I went yesterday to have it checked out and its the O2 sensor. No biggie, but annoying.

Have you guys had experience of a whining sound from the cabin at low speed? When the top is down and you are smiling from the sound of the straight 6, all seems well in the world, but I just don't want to ignore something that may let me down - especially if my wife is driving on her own late at night.

[Michael9218]

Congratulations on your purchase!

It would be helpful if you could elaborate more on the noise.
Is it only at low speed and at idle? Does clutch engagement affect it. Any specific gears?

[Piper1]

Also post indicates 2011 which might be more info in the e89 posts

[vt100]

Originally Posted by Addle66

Have you guys had experience of a whining sound from the cabin at low speed?

What's the conditions of diff bushings and trainy mounts? (and central bearing too)
Both will contribute quite a bit to the whining noise.

But generally speaking I always thought that BMW's rear diffs love to "sing".
At least on all my BMWs that was the case

[wdb]

Read original post. OP hears it when the car is sitting still. I guess the dealer really ripped him.

And yes OP, 2011 is an E89 Z4. You may have better luck there. This is the E85/6 section of the site.

[vt100]

Originally Posted by wdb

Read original post. OP hears it when the car is sitting still.

Hmm, that part I missed..

Originally Posted by wdb

I guess the dealer really ripped him.

Yeah, seems so.. though nothing out of ordinary unfortunately..