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Author Topic: Big End Bearing noise - D-Sport Facelift  (Read 228 times)

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May 15, 2018, 10:18:09 PM

X5-D-Sport Salisbury

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Big End Bearing noise - D-Sport Facelift
« on: May 15, 2018, 10:18:09 PM »
As she revs up & goes thru the auto box, if I back off the power at higher revs, I can hear what sounds like the big-end bearings banging away...

It started 2 weeks ago & got gently worse... oil & filter change didn't improve it any at all...

So, I'm wondering if there is a diagnostic mode to check oil pressure, or a relief valve that fails, or any one know if the oil pumps are known to fail or reduce oil pressure ??

The engine has done 189,000 miles, & has had 8k oil changes for the last 60k miles...
The turbo is spinning freely, & no unusual exhaust smoke or crank case smoke from oil filler.
All the fluids are the correct levels & colours.

It does seem odd that this has suddenly happened in the last 3 weeks..

Any clues or ideas or other things that can cause this sort of sound.

May 16, 2018, 12:40:34 PM
Reply #1

X5-D-Sport Salisbury

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Re: Big End Bearing noise - D-Sport Facelift
« Reply #1 on: May 16, 2018, 12:40:34 PM »
I read, that it's possible the oil pump its self may work loose & then lose oil pressure ?

Any one heard of this ?

May 16, 2018, 09:14:55 PM
Reply #2

henrym3

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Re: Big End Bearing noise - D-Sport Facelift
« Reply #2 on: May 16, 2018, 09:14:55 PM »
I would have thought that acceleration would cause more noise/problems than lifting off
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May 17, 2018, 05:45:18 AM
Reply #3

IanP

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Re: Big End Bearing noise - D-Sport Facelift
« Reply #3 on: May 17, 2018, 05:45:18 AM »
In my experience, failed bottom end bearings don't usually gradually worsen, they fail go pretty quickly. Is it a harsh rattle when you rev the engine at idle?
I have also seen defective injectors give the same noise without triggering any EMS light.
Maybe take it to a garage and See if they can connect a pressure gauge into the oil system to check the oil pump. They might also be able to pinpoint the noise.

May 17, 2018, 02:52:43 PM
Reply #4

themoog

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Re: Big End Bearing noise - D-Sport Facelift
« Reply #4 on: May 17, 2018, 02:52:43 PM »
What about the flex plate or torque converter? They can sound similar to bottom end.

May 20, 2018, 02:30:57 PM
Reply #5

X5-D-Sport Salisbury

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Re: Big End Bearing noise - D-Sport Facelift
« Reply #5 on: May 20, 2018, 02:30:57 PM »
Moog....
Please explain the Flex-Plate noise potential ?

Cheers
Grant B