[Robin427]

Hello,

after solving the problem with inconstant acceleration there is now the next problem comming up.

between ~1300rpm and ~1800rpm there is a metallic rattling (possible to described like marbles in a can ) from the engine
noticable with open windows and clos to other things like cars or walls.

currently no fault codes since 2k miles and the engine seems works fine despite a little rough idle ~5 seconds after start

after disconnecting the vanos solenoids it's quiet, so it must be the vanos

is this just a "cosmetic issue" as long there is no code or is a soon fix needed?

[bluewater328]

DISA flap?

[franksinatra]

Could you post a video of the noise?

[Robin427]

it doesen't sound like the DISA, it's more a metallic rasp noise like a loose sheet metal from the exhaust
plus - both DISA are new


i tried a Video but it's difficult, mostly the wind noise overlapped it

[franksinatra]

Originally Posted by Robin427

it doesen't sound like the DISA, it's more a metallic rasp noise like a loose sheet metal from the exhaust
plus - both DISA are new


i tried a Video but it's difficult, mostly the wind noise overlapped it

Does it sound like this?

https://www.reddit.com/r/BmwTech/com...tm_name=iossmf

[Robin427]

no, my rattling/rasping it different

it's directly connected to the rpm of the engine and with an higher frequency

and it's only while driving , while rving up the engine it's only for a very very short moment

Originally Posted by franksinatra

Does it sound like this?

https://www.reddit.com/r/BmwTech/com...tm_name=iossmf

[Robin427]

Does anyone else have an idea?

here my thoughts on this rattle:

I think it comes from the Vanos because it doesn't rattle when the Vanos valves are disconnected

I don't think it's from the Valvetronic because it stays the same with different pedal positions
(maybe someone here in the forum knows whether the Valvtronic is also deactivated in LIMP mode as soon as the Vanos valves are unplugged)

a mechanical defect (spring in the adjuster or similar) should always rattle (e.g. VW or Mercedes adjuster)

The effect on the adjustment cannot be too strong, since there are no error codes

I found a lot of carbon crumbs on the vanos filters, maybe other oil ducts or bores are dirty and under certain conditions the oil pressure in the adjuster is not enough ...

[bluewater328]

Hard to say without a little more detail. If you could isolate the sound to a region of the engine bay that would help. Possible that the cats are falling apart, but again, that's just a guess without more info.

[F31B48]

I could possibly be the VANOS hub bolts coming loose. I think there is a few threads on here about it.

[Robin427]

i know it's very difficult with this little details, i was hoping someone had have a similar issue before.
it's hard to percise the location of the rattling or make a video because it's only while driving mainly uphill
it's not noticable while reving up the engine when the car stand

it can be also described like the sound of an old TDI disel engine, and it's only when i accelerate in this rpm range

can i check the vanos hub bolts without removing the valvecover?
i remember when i replaced the eccentric shaft senor all of them looked correctly seated