Rattling noise from top end (4.8is) - help appreciated :-)

[Lion Heart]

Hi guys

Trying to diagnose a couple of issues with my new 4.8is.

There is a rattling noise from the engine. Definitely sounds like it's coming from the top end. More noticeable on the nearside, but seems to be both sides.

You can also hear the noise well from the front wheel arches as well.

I've taken two video's to show the issue (24 and 43 seconds so kept it short and sharp!) Can you guys take a look and let me know what you think:

VIDEO 1 (inside engine bay):
https://www.dropbox.com/s/ebeiblvuf2...N2718.AVI?dl=0

VIDEO 2 (outside car and wheel arches):
https://www.dropbox.com/s/5pxhkj9nb7...N2719.AVI?dl=0

What do you think is the likely culprit here?

Thanks guys!

[LVR]

Hi

I would be having a look at your spark plug coils..... sounds very similar....

Cheers

[Lion Heart]

Really, why would they rattle???

[upallnight]

Originally Posted by Lion Heart

Hi guys

Trying to diagnose a couple of issues with my new 4.8is.

There is a rattling noise from the engine. Definitely sounds like it's coming from the top end. More noticeable on the nearside, but seems to be both sides.

You can also hear the noise well from the front wheel arches as well.

I've taken two video's to show the issue (24 and 43 seconds so kept it short and sharp!) Can you guys take a look and let me know what you think:

VIDEO 1 (inside engine bay):
https://www.dropbox.com/s/ebeiblvuf2...N2718.AVI?dl=0

VIDEO 2 (outside car and wheel arches):
https://www.dropbox.com/s/5pxhkj9nb7...N2719.AVI?dl=0

What do you think is the likely culprit here?

Thanks guys!

So from the above statement, I would assume you just acquire the X? Did the previous owner give a reason why he was selling the X? Did you do a PPI prior to buying it?

Timing Guides. Drop the oil pan and see if there are bits of the broken timing guides in the oil pan. Perhaps that is why the previous owner got rid of the X. Not a cheap fix.

[Lion Heart]

I bought it from a main dealer who had taken it in part ex and was clearing it. It had been part ex'd in against a brand new car.

Has full sservice hisotry etc so not a dubious car. Just need to solve these issues.

To replace the timing chain guides - is that an engine out job???

[upallnight]

Originally Posted by Lion Heart

I bought it from a main dealer who had taken it in part ex and was clearing it. It had been part ex'd in against a brand new car.

Has full sservice hisotry etc so not a dubious car. Just need to solve these issues.

To replace the timing chain guides - is that an engine out job???

Just everything in front of the engine needs to be removed, fans, radiator, radiator support, maybe the headlights, front bumpers cover and bumper. etc, etc, etc.

[Lion Heart]

Yes, I found a video on youtube showing the timing chain replacement. Definitely a lot of strip down work, but didn't look 'too' bad I guess.

Noted the cam locking tool, which I would assume could be bought fairly cheaply from sealey or similar.

But need to make sure its definitely that, and if not then what, before undertaking that job...

[blakamin]

Timing chain guides on the N62 is a rare thing to go... Not like the M62 that ate them for breakfast.

Weird.

I'd check out https://xoutpost.com/bmw-sav-forums/...de-issues.html
and the mention of intermediate levers before going too far with guides.
But that's just me.


Edit: not saying they don't fail, just saying it's a rare thing.

[Lion Heart]

Good point. Yes, I am thinking maybe not cam chain followers because there is no rattle on cold start.

I have some experience of cam chain follower issues with Audi's, and on those because there is initially very little oil pressure and the cam chains are tensioned by oil pressure, you get a rattle on start up for 2-5 seconds.

But from memory (I'm going to double check again later!) there is no rattle on initial start. It comes in after the revs drop to their standard idle (revs are higher when you first start the engine, and settle down after 1-2 minutes, which is when the rattle becomes most evident).

Hopefully not the cam chains, that would be nice :-)

The car is nearing 120k miles.

[LVP]

FWIW here is a thread with some other video recordings. I have put 100,000km on it since these videos and not done levers or timing chain guides. I did drop the pan to inspect for plastic bits and nothing there.

https://xoutpost.com/bmw-sav-forums/...eos-sound.html