[jh_f30]

Hey guys!

I wasn't sure if I should post this here or in the N55 thread, but I figured it might get more traction here.

Recently, I've noticed a rattle when I'm driving slowly under light throttle. Actually, driving slowly might be an overstatement, I'd call it creeping. It's most noticeable when I'm creeping through a drive-thru, and there's a wall next to me to resonate the sound.

I know wastegate rattle was a common issue in N54s and somewhat in early N55s (which mine kind of is, PWG), but I heard that wastegate rattle is most common on startup, and oftentimes goes away after the car is at operating temp? I don't get any startup rattle, and it persists even when the engine is hot.

Once I get past around 5mph, it goes away, and it's most prominent only when I'm in gear, creeping forward (maybe in reverse to, haven't really checked). So basically, only when it's under load. There's only the faintest hint of the rattle when I lightly rev in Park or Neutral.

Any one experience similar? Could it actually be wastegate rattle? And if not, any thoughts on what it might be? Any and all insights will be appreciated.

Thanks!

For reference:
2013 335i automatic
Tuned with mostly FBO (no FMIC yet, but I'm leaning towards it)
High mileage commuter/daily driver (115k+ miles)

[Alpine-F80]

Sounds like the belt tensioner, a common failure point on these engines. Super cheap part and easy DIY. I did mine after noticing the exact symptoms you mentioned and doing some research. There's some DIYs on YouTube. I'm cheap so I got the non-OEM replacement and it's been great so far Bapmic 11288604266 Serpentine Belt Tensioner for BMW F30 F10 F01 F02 https://www.amazon.com/dp/B01MZZS3O9..._PTYyDbTJ88NJ8

One way to test if it's that is to turn AC on, it should become audible then. Otherwise it may just be normal injector noise, it's loud on these DI engines, it's most definitely not wastegate rattle.

[jh_f30]

Originally Posted by Alpine_F30

Sounds like the belt tensioner, a common failure point on these engines. Super cheap part and easy DIY. I did mine after noticing the exact symptoms you mentioned and doing some research. There's some DIYs on YouTube. I'm cheap so I got the non-OEM replacement and it's been great so far Bapmic 11288604266 Serpentine Belt Tensioner for BMW F30 F10 F01 F02 https://www.amazon.com/dp/B01MZZS3O9..._PTYyDbTJ88NJ8

One way to test if it's that is to turn AC on, it should become audible then. Otherwise it may just be normal injector noise, it's loud on these DI engines, it's most definitely not wastegate rattle.

Yeah, just yesterday, I actually started thinking that it might be the tensioner. Didn't initially think of it because I replaced mine less than 15k miles ago, last December (along with the belt and idler pulley). Didn't think I'd have to worry about it again for at least another year or so. I used the INPA oe replacement part, little more than the Bapmic one, but cheaper than the genuine BMW part. I know it's a fairly common issue, I wonder if using the genuine part would've lasted longer. Oh well, looks like I'll be re-ordering the part. In hindsight, I should've gone through FCP the first time around.

[Alpine-F80]

Originally Posted by jh_f30

Yeah, just yesterday, I actually started thinking that it might be the tensioner. Didn't initially think of it because I replaced mine less than 15k miles ago, last December (along with the belt and idler pulley). Didn't think I'd have to worry about it again for at least another year or so. I used the INPA oe replacement part, little more than the Bapmic one, but cheaper than the genuine BMW part. I know it's a fairly common issue, I wonder if using the genuine part would've lasted longer. Oh well, looks like I'll be re-ordering the part. In hindsight, I should've gone through FCP the first time around.

Damn, maybe see if you can tighten it first? I think leaky OFHG can cause them to wear prematurely too by leaking oil onto it.

[jh_f30]

Originally Posted by Alpine_F30

Damn, maybe see if you can tighten it first? I think leaky OFHG can cause them to wear prematurely too by leaking oil onto it.

Haha. Yeah, I replaced the ofh and oil cooler gaskets 2 days after the belt, tensioner, and pulley. Maybe I'll go back and re-torque it to spec, but I don't want to go beyond that.

[jh_f30]

UPDATE:

Just replaced the belt tensioner (again) and it seems to have fixed the issue. As I mentioned, I last replaced it less than a year ago at 102k miles. I started really noticing the rattle probably at around 114-115k miles. So I got a lifespan of around 12-13k miles. Now, my tensioner wasn't loose or jiggling at idle, which it was when I replaced it the first time last December, so I probably could've gotten more miles out of it. I was just really annoyed by the rattle.

In any case, the first time, I ordered it off Amazon for the fast & free Prime shipping. This time I ordered it from FCP Euro, so in case I need to replace it again in the next year, I can do a warranty replacement. Just a note for anyone looking to replace their tensioner, it might be worthwhile to get it from FCP in case you have similar issues in a similarly short amount of time/miles.

Reference: part # 11288604266

[Marq_z]

Originally Posted by jh_f30

UPDATE:

Just replaced the belt tensioner (again) and it seems to have fixed the issue. As I mentioned, I last replaced it less than a year ago at 102k miles. I started really noticing the rattle probably at around 114-115k miles. So I got a lifespan of around 12-13k miles. Now, my tensioner wasn't loose or jiggling at idle, which it was when I replaced it the first time last December, so I probably could've gotten more miles out of it. I was just really annoyed by the rattle.

In any case, the first time, I ordered it off Amazon for the fast & free Prime shipping. This time I ordered it from FCP Euro, so in case I need to replace it again in the next year, I can do a warranty replacement. Just a note for anyone looking to replace their tensioner, it might be worthwhile to get it from FCP in case you have similar issues in a similarly short amount of time/miles.

Reference: part # 11288604266

I know this is an old thread but just wanted to confirm, did the rattle you mentioned go away after replacing it with the new parts? I have the same issue and my ocd is acting up. I have the kit in my fcp euro cart ready to go. Thanks.

[jh_f30]

Originally Posted by Marq_z

I know this is an old thread but just wanted to confirm, did the rattle you mentioned go away after replacing it with the new parts? I have the same issue and my ocd is acting up. I have the kit in my fcp euro cart ready to go. Thanks.

Yes. Completely resolved the rattle I was getting. How many miles on your car? If you've got a decent number of miles and it's your first time doing it, it might be a good idea to go ahead and order the idler pulley and a new belt while you're at it. They're relatively inexpensive and if you end up not needing the belt right now, you've at least got it on hand. Though, if you've got it all apart anyways, I'd figure, might as well replace it all as preventative maintenance.

[Marq_z]

Originally Posted by jh_f30

Yes. Completely resolved the rattle I was getting. How many miles on your car? If you've got a decent number of miles and it's your first time doing it, it might be a good idea to go ahead and order the idler pulley and a new belt while you're at it. They're relatively inexpensive and if you end up not needing the belt right now, you've at least got it on hand. Though, if you've got it all apart anyways, I'd figure, might as well replace it all as preventative maintenance.

Thanks for the info. I have about 77k on it now, I bought it at 73k. I noticed a knocking sound about a month after I bought it and a similar noise to your video at initial throttle which from my research I came to assume is do to the tensioner because it has a bit of play. Anyway, I will go ahead and order the kit soon and hopefully it'll get rid of the knock and rattle for a while.

[Chaos236]

Mines at 40,000 getting ready to do it, any DIY videos or directions?
Thanks

[jh_f30]

Originally Posted by Chaos236

Mines at 40,000 getting ready to do it, any DIY videos or directions?
Thanks

This was actually posted recently.

I haven't watched it personally, but Bryan's vids are generally pretty good. You can cross-reference with this:

https://www.newtis.info/tisv2/a/en/f...ement/EXLFoWGh

[Chaos236]

Thanks, will order belt and ideler pully also.
How hard on a 1-10?
Thank you for posting.

[jh_f30]

Originally Posted by Chaos236

Thanks, will order belt and ideler pully also.
How hard on a 1-10?
Thank you for posting.

If you have the right tools, I'd say 3-4. Definitely need a breaker bar to "re-cock" the tensioner.

[Chaos236]

Thanks again, going to order the deflection pulley and a new belt. Its all very noisy .

[MohDarawsheh]

Hi all

Was it the chain tensioner

I will share a video soon of the ticking noise.

Best