Tracking down an annoying rattle (chain rattle)

[m3f_I3MW]

So I did my VANOS two weeks ago.


Install went fine. I started up the car and it had what I would describe as a chain rattle (it was more noisy than before). After giving it some time to smooth out and settle down, the noise did not go away. I thought oh ****, I messed something up. After talking to chris and another BMW specialist they assured me if my timing were off I would have already bent valves and we tried to trouble shoot. Long story short I finally drove the car around a bit before bringing it to this specialist (BMW indy shop I know apparently sends there internal engine work here). They told me they couldn't really find anything :-) the only thing they could do was check my timing since I did not use the fly wheel pin and see if there was anything wrong. I told them do the secondary chain tensioner while you charge me and arm and a leg. Long story short I was told that "I did a good job, also the timing was spot on" :-). Drove it home, it drove nice, just as it did before I brought it to them, I did notice the general chain noise that I was hearing was gone (it happened from idle to 2k) . THe next time i turned it on and drove it, I could hear a more distinct, more annoying sound around 900 rpms that was louder with a blip of throttle rather than holding it. Drove it around, thought it went away but really you just can't hear it unless it quite out, meaning not driving around/next to other cars or myabe in a really busy shop, ect. But it is most definitely there. Any ideas guys?


Next step for me is to have to deal with these guys, they are not gonna be to happy to see me again (they don't exactly like DIYers to begin with)


Sorry for the essay but I'm convinced the answer to this really annoying problem is in the details. I'll try to get a vid/sound clip tomorrow.

[m3f_bigneil]

Are you sure it's not just the catalytic converter or exhaust rattling? That's been the main source of rattle for me.


Generally, if the car chirps second gear, it's fine.

[m3f_burger]

I thought I had a timing chain rattle, replaced the tensioner, no luck. Turned out to be a shot tensioner pulley for the belt. Worth a shot to check.

[m3f_Schalldampfer1]

I have the exact same problem. It seems to go away at higher RPMs and quiets down at lower RPM's after driving for a while. It is strange. I wish I knew what to do to get rid of the noise.

[m3f_Synenergy52]

I too have a slight chirp-chirp-chirp/rattle noise which I've just learned to deal with. The noise persists despite replacing virtually everything on the front of the engine--every belt, tensioner, accessory, fluid, nuts bolts. I think it's my vanos.

[m3f_Schalldampfer1]

So my mystery "chain rattle" noise has stopped out of nowhere. It had been making that noise for over a year and it stopped the other day and I didn't do anything specifically to stop it. Very strange but now my M sounds normal again! Hooray!!

[m3f_Petrucci]

Originally Posted by Schalldampfer1:

So my mystery "chain rattle" noise has stopped out of nowhere. It had been making that noise for over a year and it stopped the other day and I didn't do anything specifically to stop it. Very strange but now my M sounds normal again! Hooray!!

Wow that works for me.


I'm still trying to track down my noise at deceleration. It only seems to occur in second and first gear only at around 1k to 2k rpms on when you let go of the exhaust.


Sorry for the hijack OP :-) hope it all works out for you!

[m3f_Volcom8190]

Did you replace the lower timing chain tensioner?


I have the same issue as you, replaced the same parts but have not replaces that.


I know my lifter tick is associated with some minor scoring on the cam trays.

[m3f_ANT'S M3]

what oil are you running OP?

[m3f_I3MW]

When I first bought the car BMW's 5w-30, I knew I didn't want to stick with that (not because it's bad I just new I wanted a little thicker oil when up to temp). So for most of the time I've owned it, it has been Amsoil Euro 5w-40. Last oil change was shell rotella 5w-40, those three are the only ones I've ever used.


Replacing the tensioner (secondary) near the VANOS did nothing. If anything it made that weird specific resonance of rattle (900ish rpm) but that went away after less than a 100 miles (really after I drove the car more than twice) . So that was propably typical break in and perhaps moving the rattle to what now became the weakest link if you will (the other chain and tensioner).


I'm hoping to do the primary this weekend, and I hope it will solve the problem. I'm not looking for perfection but a smoothing out the kinks or just quieting down any of the "noisy-ness" the VANOS install did not take away would be nice.


I will let you guys know for sure.


BTW can anyone confirm: There is no updated design for the OBDII tensioner it's just the standard part number, correct? Also is there a sealing ring or gasket? And finally how easy is the install... Just pop the old one out with a 32mm wrench and torque the new one to spec, right?


EDIT: so just to clarify and to give cliffs for the original problem. The noise that occurred after the install of the secondary tensioner went away once I put a couple miles on the car. Changing my VANOS made some of "excess" engine noise go away. I could definitely tell by comparing, that my old unit did have a lot of axial play and the new one had none that I could tell of. I did not really feel an increase or restore in low end power, but then I never had surging issues. Interestingly, if I am totally honest the car just feels faster, I would say more from 3-4.5k rather than below, which I know doesn't make as much sense but just telling it as I experience it.