Oil leak - grinding noise

Discuss the problems with your X5 (E70).
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Joined: Thu Jul 30, 2020 8:04 pm

Oil leak - grinding noise

Thu Jul 30, 2020 8:15 pm

Started noticing a noise like my pads and discs needing doing, as it happened the discs should’ve been replaced by the previous owner when he did the pads as they were knackered.

Had new discs and pads done all around but noise was still there, gets louder the faster i go, doesn't disappear when i brake.

Not always there 100% of the time though. Like earlier travelling in circles around a car park, sounded worse on one lock that the other, then hour later couldnt really hear it. Noise is front right wheel area to my ears

Now today I’ve noticed an oil leak from the front, clearish fluid so not engine oil, smells like cat piss, not air con as that was a seperate puddle which didnt smell of anything.

Could the cat piss oil and grinding sound be related, I’m scared it might be something transmission related.

Going into the garage on monday, any heads up or thoughts what it might be? Thanks

E70 2013 xdrive 30d 58k
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Re: Oil leak - grinding noise

Thu Jul 30, 2020 9:52 pm

Grinding noise could be a wheel bearing, but with a smell like that, it could also be the front differential area. Worth checking the driveshaft boots for leaks or wetness cause by overheated grease.

If it is the diff then that could just be caused by incorrect tyre choice. xDrive cars have challenges with tyres! Ideally they should carry a ‘*’ mark on the sidewall (indicates made within the BMW spec) and have less than 1.5mm of tread depth difference between the axles. All four tyres should be the same make & type. This is especially important on cars with different width tyres on the front/rear axles - as most BMWs do - as wrong sizes or wear difference cause transmission wind up.

The usual clue is to drive very slowly and on full lock. If there is any jerkiness your diff needs attention. If the noise is a little further aft then the transfer box could be the source. It can happen with the right tyres fitted, but is much rarer. We do have a resident transmission expert - kkx5 - although he hasn’t been on here for a while.

One other check is to have a close look at the front propshaft. There was an issue with certain models where the shaft fails. Yours is later than the ‘problem period’ in 2010/11, and should be fine for that issue.

The only other fluid I can think of is power steering - usually pink though.
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