[wazefan]

Hi guys! I just bought a well maintained high mileage e90 328i about a month ago and have started to notice a loud metallic rattling sound coming from the front of the vehicle. It is mostly present on start up, when accelerating, or when revving in neutral. It's not noticeable with the windows up, but is pretty loud when they're down, and there aren't any unusual vibrations accompanying the noise. The car seems to drive fine still besides the sound... any ideas or similar issues? I'm a bit worried its the timing chain, since the car has a bit over 200k miles and still hasn't had that service, but it seems like that's a rare issue on these cars.

[Serf27]

Possibly the belt tensioner.

[wazefan]

Ahh I should have mentioned in the beginning that that was my original thought as well, since the tensioner was visibly failing too. I ended up replacing it today, and it didn't fix it. Feels bad having overnighted the part from FCP for nothing since I was planning on road tripping the car this weekend Thanks for the reply though!

[gardar]

Vanos?

[wazefan]

I'll check it out, thanks! I'll link a video of the sound for reference too:

https://youtube.com/shorts/pTeqrJJkaTQ?feature=share

A friend that's more experienced than me also said it sounds like an exhaust rattle or something similar from the video.

[mainbearing]

DISA valves rattle?

Also remove the oil filter cap and make sure the center cage is on there. If not then oil will drain back through the small center drain into the crankcase. Also, the pressure relief valve would be hard to see inside the cage, make sure it is not missing.


https://www.e90post.com/forums/showt...1797512&page=2

[e90yyc]

I have what I believe is the same or at least very similar noise and I’ve got no idea what it is.

Practically every wearable part on my car is new or near new, including belt and tensioner. There can be issues with VANOS bolts backing off, but these issues affect only certain model years. Mine was not one of them, and not surprisingly, visual inspection of the VANOS tensioner bolts confirmed they were all intact and tight.

What year is your car?

As I understand it, the VANOS systems can become a little noisy when you reach higher mileage, but that outside of specific circumstances (e.g., tensioner bolts backing off/sheared) it isn’t cause for concern. I’ve just learned to live with it, but I’m definitely open to reasonable fixes.