Quote:
Originally Posted by FormulaMMM
Thing is, you may very well have heard it. It's intermittent for many, including me with both of my E90s. Absolutely does not happen on 100% of starts. OP in this thread has had numerous perfect cold starts while in the process of trying to resolve the issue. Next time yours sits for a chunk of time, take a close listen again.
Based upon all of the forum discussion on this topic, and all who have chimed in to say they've experienced, it can be reasonably concluded that it's not outside of the norm to have the noise. "Normal" as in what M expected? Can't say. Both of my E90s (separated by 2 model years and 25k miles) have it. If it was truly a rare issue, the chances of that I'd acquire 2 of the uniquely afflicted are slim to none. Others have also had two E9Xs with the issue.
Also can be reasonably concluded based upon the available data that it is not indicative of a near term or long term serious (or even minor) engine issue.
All of that said, I certainly hope we get confirmation on the Vanos cause. If so, what characteristics of the used Vanos are creating the noise, and are they in some way compromised?
Considering this occurs on cold starts, and most commonly after the vehicle sits for a while, I have a suspicion this is much to do about a lubrication issue...
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What's even stranger is the fact that M3PO's Vanos Gears Bank 1-4 was replaced and fixed the problem,so the clunck noise was history !
Ok good to know...But now,and i've said it before...
So pulling the Vanos Gears Bank 1-4 out ,and put the same of the factory Vanos Gears back in ,and this is the fix with the same Vanos Gears of the factory ?
It's almost like pulling a problem out and put the same problem back in ?!?!
Something is just not right ...and personal i'm thinking it's more like backlash of the Vanos Gears and creates the clunck noise during the start up !
And it's just that i don't get ???
Same thing is with the brake procedure for DCT's each time when i'm doing this i've no clunck noise ? And maybe it's a sign that the Vanos Gears have the necessary time to tension (during the 30 sec.brake procedure) and so there is no clunck noise ?
Not sure about this and so maybe i'm wrong.....but it seems that way !