Engine whine synced to revs, power steering pump? [video with sound]

[jmscdgn]

Hi TB’ers

Happy weekend to all.

If anyone has the time to throw in their 2 cents on the following sound coming from our 740t engine bay, it would be much appreciated.

Power steering fluid levels are good, though it does appear to be coming from that area though fining it hard to pinpoint— initially thought it was alternator bearings. Hoping if anyone is intimately familiar with this sound, they could shed some light.

Thank you,
J

 

[Khrrck]

If you push the wheel all the way to full lock and hold it there (putting more load on the pump), does it get any louder?

 

[the_hairy_baboon]

very linear with engine speed, so basically has to match with something spinning with engine. Would need a spectrum analyzer to say if the noise is 1:1 with engine speed or a ratio thereof.

Could try taking off belts to see if noise stops. Also try having someone dampen various components (press against non-moving portions with hand or object, basically change the natural frequency).

Does the noise sustain if you rev up then key off (i.e. cut combustion)?

 

[jmscdgn]

If you push the wheel all the way to full lock and hold it there (putting more load on the pump), does it get any louder?

Thanks for your reply. It doesn’t appear to get louder when full lock. There is a usual (for me at least) “straining” type whine when holding at very hard lock, the steering wheel then feels to have a little motorised push back - just a degree or two - as though the PS pump is saying “no thanks”, and the straining sound goes.
The hard lock straining whine seems distinct from the one closely tied to the revs.

very linear with engine speed, so basically has to match with something spinning with engine. Would need a spectrum analyzer to say if the noise is 1:1 with engine speed or a ratio thereof.

Could try taking off belts to see if noise stops. Also try having someone dampen various components (press against non-moving portions with hand or object, basically change the natural frequency).

Does the noise sustain if you rev up then key off (i.e. cut combustion)?

Thanks for the reply too. I just ran an errand and now with engine at operating temp the noise is a little less pronounced—could that be a clue?
I’ll run the key-off test when it’s cooled down. Thanks again.

 

[cosbySweater]

Sounds like your transmission. Take the converter bolts off and try again. However before that I would take the belts off and make sure it's not a accessory. To me it sounds like transmission

 

[MasterBlaster]

Mechanic's stethoscope.
Piece of vacuum hose stuck in your ear and pointed at/on various things.
Screwdriver with hard handle to feel vibrations.
Many ways to identify odd whining noises and bad bearings.

 

[ZVOLV]

Cheap stethoscope to start with.

Then loosen/remove belts.

It could be a bad timing belt bearing.

 

[jmscdgn]

Sounds like your transmission. Take the converter bolts off and try again. However before that I would take the belts off and make sure it's not a accessory. To me it sounds like transmission

Mechanic's stethoscope.
Piece of vacuum hose stuck in your ear and pointed at/on various things.
Screwdriver with hard handle to feel vibrations.
Many ways to identify odd whining noises and bad bearings.

Cheap stethoscope to start with.

Then loosen/remove belts.

It could be a bad timing belt bearing.

Thanks all. I’ll find some time this week and report back. Cheers