[proj335i]

Hi guys, having the car for six years now, love/ hate relationship, I know I am not the only one haha

So, my car was stored for winter, started the engine yesterday, everything is fine on start up. After around 5 minutes of idle, an annoying rattle appeared on idle and low rpm and stays even when fully warmed up. Lifted the car on ramps , took the belly pan off but I can not tell for sure where it's coming from. It might be from the turbo/ actuator area but I am not sure.

And the rattle gets way quieter when I put load on the engine through accessory belt like when I turn AC on or rear defrost.

Video below, thanks for your help!

6mt 2011 e90 335i, Pe exhaust, vrsf catless dp, MHD stage 2

[proj335i]

[siloansa]

Originally Posted by proj335i

+1

[JUMAS]

is that your exhaust flap rattling? lol

[proj335i]

No , PE exhaust installed

[proj335i]

Anyone ever heard that kind of rattle and especially this loud? Can a rattling wastegate be this loud and constant?

[proj335i]

I thought about a loosen vband clamp but no, vrsf downpipe is tight and the vband is still perfectly tight as well. DP been there for four years without any problem, would have been very surprising... nothing loose in exhaust system as well.

But I am very confused now and out of ideas, anyone can chime in? Car has only 50k miles

Thank you!

[proj335i]

No codes whatsoever, a faulty vacuum pump cause cause that wastegate rattle? Never heard that rattle until now and it is very loud, I thought a wg rattle would get progressively louder, definitely not that loud at the first place.

[proj335i]

Hey guys, , two years later, havent found the issue yet! Car still running great beside that sound. Anyone has experienced something similar?

[TLMNICK]

I would get your hands up and around the wastage actuator and check for excessive play.

[Street of Rage]

Reviving this... my car starting to do the same, a slight moment during cold start and when the car is accelerating slowly around 1300rpm and disappear after 1600rpm or so.
I think it's the wastegate chatters/rattles from wear and tear. The car has 111,800 miles.


Update:

Turned out bottom pipe clamp and its bolt were gone. The rattle sound a bit different from the video in this thread. I probably forgot tighten it secure after my transmission service back in end of 11/2023 . I don't want to justify $40+ for the missing 2 pieces. A quick fix method by using M8x60mm bolt (from Lowes), drilled into a center piece of metal, use semi thread lock, and bolted up to the top clamp temporarily.