I get this intermittent rattle when I start the engine:
http://gallery.me.com/nardeezy#100650

See the third start (7/4@1803) at approx. 22 seconds. The dealer could not re-create. THey thought it was a heat shield so they re-positioned/formed one of the heat shields but I still get the rattle sometimes. Any thoughts?

 

Anybody?

 

It's really hard to tell from the video but it almost sounds like piston slap. Does it ever do it when it's hot or only when it's cold? Does it keep making that rattling noise for an extended period of time if you give it some gas right afterwards or is it just that first split-second after start?

My FD would slap like crazy when I'd start it in the winter (much colder than CA) and sounded much the same but for quite a lot longer period of time.

 

It does it intermittently after the car has been sitting for a while and you can only observe the rattle for about a second and a half after the initial engine start.

 

I'm too lazy to listen to the clip, but it sounds likely to be hydraulic tappets/lash adjusters pumping up. Tappets usually get described as a tapping sound though. Very typical of the M112 and M113 motors. Nothing to worry about. Using the correct M1 0w-40 motor oil permits the tappets to bleed down when the engine is not running. It's actually a good sign, indicates the engines is not sludged/carboned up - then the tappets get stuck and don't tap - or self adjust.

 

Sounds interesting but why would it do it intermittently (even on cold starts) and why didn't it do it on my previous E63? This is my 2nd E63 because the dealer had to swap out the other one because it had issues too.

 

Oh, never mind. I didn't notice you had an E63. I'm familiar with the M112 and M113 motors, as used in the E320, E430, E500, E55, etc. The E63 is a completely different animal.

 

Shot in the dark - but if it only when it is cold perhaps the secondary air pump, as that is only used on a cold start. Could be a hose or something related to that?

 

It's interesting how nobody thinks it's the exhaust?

 

What's a secondary air pump?

 

I'd say lifters or the timing chain tensioner. Are you due for an oil change, I notice as it gets closer to oil change time for me on the 55 engine the lifters begin getting noisy.

Exhaust sounds damn good though.

 

I bought the car as a CPO and the oil change was done on 4/15/10.

FYI, I have a small dent on the right exhaust pipe located between the rear differential and muffler. If I tap the left exhaust tips with a mallot I hear a small rattle. WHen I tap the left exhaust tips I get no rattle.

 

Just to close the loop on this, it has been resolved for quite some time now. It took three separate dealer visits but they were finally able to replicate the sound and the root cause was due to a faulty camshaft adjuster. About 5,500 miles later and everything seems to be okay.

 

I have noticed too many folks ask for advice, members offer suggestions, and when the problem dissolved the questioner does not close the discussion as you did.

 

Hi there nardeezy,
Would it be possible for you to reload the clip that you originally posted. I am currently trying to locate a rattle in my E55 that sounds like a loose exhaust baffle at cold start.
regards

 

no need. This issue hasn’t been resolved and it’s isolated to the M156 motor only.