Engine making loud noise, what is it?

e39power · 25th September 2010, 20:28

Looking for some help with engine noise. I originally thought the noise was VANOS related, see previous post VANOS rattle continues after startup, no codes, but it is so loud that I'm thinking it may be something worse like a broken chain guide or rod knocking. Would a sticking valve be loud? this is more than a slight ticking.

It seems to be coming from the top end on bank 2 and there are no codes. When I first start up the engine it will idle without the noise until I give it some gas, then the noise is constant even when going back to idle. So far I've checked the following:
-drained oil and checked filter, no debris
-removed chain tensioner, spring was not broken although it was not tapered on both ends like the one here Chain tensioner change DIY with pics
-removed bank2 valve cover, no scoring on the cam lobes, tensioner for the cam chain is tight. I did notice there is some play on the chain that runs back to bank1, right about where #4 is in this diagram - is this normal?
RealOEM.com BMW E39 M5 Timing - Timing Chain Lower P

Any other ideas while I have this opened up? I may just bring it to the dealer and see what they come up with

update: just noticed I can turn the little 10mm coupler on the vanos gear...dont think I should be able to? as I remember it connects to the vanos unit and should be tight? I can't get TIS to install on win7 which is unfortunately all I have right now. #2 in the diagram here for the exhaust cam, you can also just barely see in the pics below
RealOEM.com BMW E39 M5 timing gear timing chain top

mondeoman · 25th September 2010, 20:46

OH

MY

GOD!

What a lovely clean engine!!

Sorry, no other comment than that at the mo

blackxs · 25th September 2010, 23:31

From the pictures I do not see anything noticeably wrong but with an engine that clean you should have a pretty easy time pinpointing the problem!

It could be a few things, of which you seem to know most of them. Run through the engine and visually confirm everything looks ok

Cemessi · 25th September 2010, 23:48

Its alot cleaner than mine. Lower mileage I suspect.

e39power · 26th September 2010, 00:24

saw a few posts about chain guides wearing/breaking on higher mileage, mine is only at 60k
Rattling noise at idle and engine shut off
scary engine sound

I'm really not sure what else to check, I dont want to tear down the whole engine to check the chain guides.

I think I'll take the other valve cover off and see if the vanos hex coupler turns there too. And take the lower oilpan off but then I'm out of ideas.

update: bank1 vanos coupler moves too, and the oilpan was spotless...guess I'll put it back together and see what the dealer says. maybe something just got stuck in the alternator

e39power · 28th September 2010, 03:42

so I'm back to the VANOS theory again. I found this clip of youtube, not mine, but making the exact same noise. I don't think this is the "deisel noise" that is associated with VANOS?
YouTube - E39 BMW M5 Intermittent Rattle Clattering Noise !! Vanos ??

pjfox23 · 28th September 2010, 04:03

Does the noise change pitch/intensity/sound if your give her some gas?

mondeoman · 28th September 2010, 12:09

That little coupler should be free to rotate - it doesn't twist the adjusting cams, it just moves them in and out.

e39power · 28th September 2010, 18:38

well this was one odd problem, very relieved it is over with. 1 of the 3 bolts of the p/s pump was just slightly loose and causing the rattle. don't know how I didn't see that earlier but at least I know the engine internals are in good order.

Cemessi · 28th September 2010, 18:39

Glad you found it. I heard of oil pump bolts being loose on E36's I think. Makes you wonder...