new CCV hoses fixed startup rattle?
 

Cannot directly correlate the two, but have had startup rattle for about 1 second duration on cold starts since purchasing the X5 a little over a year ago. New chain tensioner didn't fix it. My thoughts have just been Vanos or lifters. But last night I just finished replacing all the CCV/oil separator hoses and when I started it, dead quiet. Well, no rattles, but made all the correct other sounds. And this was definitely a cold start, last driven on Saturday (4 days) and about 34 degrees ambient.

BTW, I did the hoses and a new CCV/backing plate while leaving the intake manifold on. It wasn't as bad as I thought it would be, X5's have so much more room back there than the 540/740's do. It was kinda weird doing all the work while perched on top of the engine though, first time I've done that I think.

Glad to hear you were able to get it done without removing the manifold! Did you replace with all the insulated hoses and cold weather version CCV (aka the insulated version?)

EDIT: On a 4.6 you did this?

only one choice on the V8 that I know of. I think the insulated hoses and CCV are specific to the 3.0.

And I have replaced the CCV on a 3.0 without removing the manifold, but I don't think I would ever attempt that again. The intake wiring harness on the 3.0 is the max I would do leaving the manifold on. Even that is pushing it though.

ahhhh nvm the v8's are a bit simpler, 3.0 gives you more than a few "choice" words during R&R

I used some of those words when I did that 3.0 CCV on a customer car. I avoided any service tickets with similar symptoms after that (honking sound). Luckily I 'retired' as a paid mechanic before those CCV's started getting clogged up.

Choice words? Hell, I wrote an entire dictionary of NEW words while I did my CCV...:bustingup