N62 4.8 clanking on cold start

[svvg]

Grateful for some thoughts on the following.

My car is a 2004 E53 with an N62 4.8 - 106,000 miles. From cold it makes a clanking noise on start up - which sounds pretty serious.... it completely goes away as the engine starts to warm up...

I’ve changed the tensioner and idler pulley and water pump - plus new belt - all BMW parts. I’m hoping alternator... but fearing chain, chain guides and tensioners?

Made a couple of videos... many thanks!

https://youtu.be/1EydUF8_ED0

https://youtu.be/FUKhYLBSIoM

[henrym3]

Holy Sh&t, that is horrific, don’t know what that is but I’d start by removing the auxiliary belts which would eliminate all the pulleys. Check the starter isn’t staying engaged. At least that will eliminate exterior sources

[Rick G]

Did you try turning the Alternator and water pump by hand when the belts were of. If not remove the belt and try them.  I would be suspecting one of the two and even possibly the power steering pump.

[Alan Gunn]

I would go with Henry on this and take the belts off first.

[Greydog]

Aren't the hydraulic tappets and intermediate fingers a known cause of noise/issues with the 4.8. Hope it isn't that as it will be expensive.

[svvg]

Okeydokes.... started it this morning. Same noise (as was cold). Shut it down and whipped off the audillary belt. Started it up and completely quiet... (so hopefully l....) phew!

I spun the alternator by hand. Smooth and silent.

Power steering pulley has a knock on it:

https://youtu.be/CeuNubMAXFQ

What do you reckon?

As soon as I put it all back together the car was silent again.... not sure if spinning the power steering pump in reverse (as I span it back and forth) maybhave lubricated it differently to normal - but am starting to think that it’s the culprit...

Thanks again for input - been on forums for years now and appreciate the advice (and try to help others back too!).

[henrym3]

If the pump was making a noise initially when you spun it, you went backwards and now the noise is gone, my bet that is temporary, it will restart at the most inconvenient moment again. If your confident it’s the pump then change it. New, recon or used, whatever the budget permits.

[Alan Gunn]

You have found your problem.
Power steering pump.

[svvg]

Yup. I reckon so. Maybtacjle the alternatirbbracket oil leak at the same time while I’m messing about with it...(!).

Thanks!