[reficuliu]

Hi Guys,

I've gone through many many threads regarding engine rattle noise. Somehow none of the suggestions have fixed my problem. I've had that rattle for a while now. It occurs from 1800-3000 rpm, and happens in every gear. Below or above that rpm range, i hear nothing. It doesnt seem to be affecting my performance, but it really is bothering that crap out of me. I took it to the dealer, and the tech heard it. They said it was an issue with the waste gate (after i suggested that he check it out, from the suggestions from e90post). They "fixed" it and said the part on the waste gate was replaced. However, i STILL hear it. Today i came across a video, with another 335i that recorded the sound. This is the EXACT sound i have, but i still dont know what to tell the dealer when i bring it in. Anyone have any advice? Help plz!!

Here's the link to the sound

http://www.youtube.com/watch?v=uyh4Cx7xY64

[Trojan4evr]

wastegate rattle, before 09 models the wastegate actuator rod was 6mm in thickness. After 09 they made them aprox 8mm thick so there won't be place left for play and rattle. make sure when they fixed it they did that retrofit. Dealership is trying to avoid changing the turbos since it is the ultimate remedy. good luck man.

[DR_E92]

Originally Posted by Trojan4evr

wastegate rattle, before 09 models the wastegate actuator rod was 6mm in thickness. After 09 they made them aprox 8mm thick so there won't be place left for play and rattle. make sure when they fixed it they did that retrofit. Dealership is trying to avoid changing the turbos since it is the ultimate remedy. good luck man.

+1 typical wastegate rattle. Ask to see proper documentation of the work performed during the last visit

[reficuliu]

Thanks guys!
I'll make an appt to have that taken a look at. .. this will be the 3rd attempt bringing my car in to have this problem diagnosed ... . . a real pain, and way too much down time .. ..

[reficuliu]

Hi Guys,

Just to follow up on the rattling. I finally brought my car to New Century BMW in Alhambra as my friend suggested it as a reliable dealership. Ends up it isnt an issue with the wastegate, and i'll post the write up for the service. This may be specific to my car only, or may help another member with the same issue. Just for reference (for anyone who comes across this.)


Issue: Metallic rattle from undercarriage between 1800-2500 rpm.

Cause: 1199 Engine Misc.
3317 W 0.00
1 24-00-417-517 Set Alu. Screws Automatic
TR: 24951010
2 17-21-1-742-636 O-Ring: 178520

27555 Broken Trans Bolt verified cust complaint, heard a metallic rattle noise coming from underneath vehicle. Removed all bottom splash panels. Visually inspected undercarriage for damages, no damages were found. Installed electronic chassis ear around exhaust area. Test drove and heard noise through chassis ear. Checked and found bolt that holds exhaust bracket to transmission bracket was loose. Re-secured bolt. Test drove, heard a rattle noise, but was not as loud as before. Re-positioned chassis ear around transmission area and turbo area. Test drove, and rattle noise was heard through chassis ear. Found rattle noise coming from transmission area. Removed all heat shields for further inspection. Upon removal of heat shields, found 2 transmission bolts missing. Found bolts that secure catalytic converter bracket to transmission bellhousing were missing. Found vibration from bracket to trans causing rattle noise. Using inspection mirror, inspected transmission bolt holes and found 1 bolt completely missing and 1 bolt broken inside trans bellhousing to engine block. As per TSE authorization, remove trans and repair bolt hole. Removed exhaust system and all heat shields. Removed drive shaft. Drained and saved trans fluid. Removed bolts for torque converter, removed trans cooler lines. Installed trans jack. Removed complete transmission. Performed extraction of broken bolt and cleaned and re-threaded bolt hole on rear of engine block. After repair, cleaned all surfaces and reinstalled transmission after tightening torque specs. Reinstalled trans cooler lines, adding 2 new O-rings. Reinstalled drive shaft, heat shields and exhaust. Re-secured torque converter bolts. After reinstalling everything, topped off trans fluid using original fluid. Checked for leaks, none found. Started vehicle and rattle noise can no longer be heard. Reinstalled chassis ear around previous noisy areas and test drove, rattle noises can no longer be heard. Reinstalled splash panels, test drive, no abnormal noises can be heard.


So the noise is gone, and im not familiar enough with this technical jargon. For anyone who read this, any suggestions as to how this happened? Sounds like there were a lot of missing/broken bolts. Is this "natural" wear and tear, or does someone think the previous owner (im the 2nd owner) may have somehow damaged the transmission/exhaust system?

[scheherazade]

Originally Posted by reficuliu

Hi Guys,

Just to follow up on the rattling. I finally brought my car to New Century BMW in Alhambra as my friend suggested it as a reliable dealership. Ends up it isnt an issue with the wastegate, and i'll post the write up for the service. This may be specific to my car only, or may help another member with the same issue. Just for reference (for anyone who comes across this.)


Issue: Metallic rattle from undercarriage between 1800-2500 rpm.

Cause: 1199 Engine Misc.
3317 W 0.00
1 24-00-417-517 Set Alu. Screws Automatic
TR: 24951010
2 17-21-1-742-636 O-Ring: 178520

27555 Broken Trans Bolt verified cust complaint, heard a metallic rattle noise coming from underneath vehicle. Removed all bottom splash panels. Visually inspected undercarriage for damages, no damages were found. Installed electronic chassis ear around exhaust area. Test drove and heard noise through chassis ear. Checked and found bolt that holds exhaust bracket to transmission bracket was loose. Re-secured bolt. Test drove, heard a rattle noise, but was not as loud as before. Re-positioned chassis ear around transmission area and turbo area. Test drove, and rattle noise was heard through chassis ear. Found rattle noise coming from transmission area. Removed all heat shields for further inspection. Upon removal of heat shields, found 2 transmission bolts missing. Found bolts that secure catalytic converter bracket to transmission bellhousing were missing. Found vibration from bracket to trans causing rattle noise. Using inspection mirror, inspected transmission bolt holes and found 1 bolt completely missing and 1 bolt broken inside trans bellhousing to engine block. As per TSE authorization, remove trans and repair bolt hole. Removed exhaust system and all heat shields. Removed drive shaft. Drained and saved trans fluid. Removed bolts for torque converter, removed trans cooler lines. Installed trans jack. Removed complete transmission. Performed extraction of broken bolt and cleaned and re-threaded bolt hole on rear of engine block. After repair, cleaned all surfaces and reinstalled transmission after tightening torque specs. Reinstalled trans cooler lines, adding 2 new O-rings. Reinstalled drive shaft, heat shields and exhaust. Re-secured torque converter bolts. After reinstalling everything, topped off trans fluid using original fluid. Checked for leaks, none found. Started vehicle and rattle noise can no longer be heard. Reinstalled chassis ear around previous noisy areas and test drove, rattle noises can no longer be heard. Reinstalled splash panels, test drive, no abnormal noises can be heard.


So the noise is gone, and im not familiar enough with this technical jargon. For anyone who read this, any suggestions as to how this happened? Sounds like there were a lot of missing/broken bolts. Is this "natural" wear and tear, or does someone think the previous owner (im the 2nd owner) may have somehow damaged the transmission/exhaust system?

Transmission [bellhousing] was missing a bolt and another was broken [where it bolts to the engine block].

Exhaust system [catalytic converter portion] was not attached to the transmission [bellhousing] like it should have been.


note :

Transmission bellhousing is the area that connects to the engine.
It's shaped like a bell : Large where it bolts to the engine block, small where the transmission starts.

It's the bright silver part in this picture:



-scheherazade

[reficuliu]

Originally Posted by scheherazade

Transmission [bellhousing] was missing a bolt and another was broken [where it bolts to the engine block].

Exhaust system [catalytic converter portion] was not attached to the transmission [bellhousing] like it should have been.


note :

Transmission bellhousing is the area that connects to the engine.
It's shaped like a bell : Large where it bolts to the engine block, small where the transmission starts.

It's the bright silver part in this picture:



-scheherazade

Thanks! Yeah i ended up doing a little bit of research. Do you know what could be the possible cause of this? (damage, crappy build, wear & tear, etc.. .)

[petermatan]

When I was putting my downpipes on, I noticed that one of the aluminum bolts that holds the bell housing to the engine was not tight at all. When I went to tighten it I saw that it was actually snapped in half. Pulled the bolt out and the other half of it was still left inside. I ended up putting glue on the end of the bolt and taking the other half out very carefully. Since then I just check all main bolts etc. about once a month.

Everything on this car is made out of aluminum which means that everything gets quite hot and then cold, that translates into loose screws.... I actually have tighten many other bolts and nuts on top of the engine that have vibrated loose. Also use lock-tight where needed, trust me on that one. This is the only car that I have seen with that many loose screws

[reficuliu]

Originally Posted by petermatan

When I was putting my downpipes on, I noticed that one of the aluminum bolts that holds the bell housing to the engine was not tight at all. When I went to tighten it I saw that it was actually snapped in half. Pulled the bolt out and the other half of it was still left inside. I ended up putting glue on the end of the bolt and taking the other half out very carefully. Since then I just check all main bolts etc. about once a month.

Everything on this car is made out of aluminum which means that everything gets quite hot and then cold, that translates into loose screws.... I actually have tighten many other bolts and nuts on top of the engine that have vibrated loose. Also use lock-tight where needed, trust me on that one. This is the only car that I have seen with that many loose screws

Sigh, i guess these loose bolts are not uncommon. I'll just keep my fingers crossed and hope for the best .. (and periodically check.. ).
Thanks for all the input!

[dyezak]

Sounds like you may have purchased a previously modified car... And it was de-modded to trade it in. Those points were the bolts were missing/broken are all common bolts to touch when modifying the car. Missing downpipe support bolts = possible aftermarket downpipes before. Missing/broken transmission bellhousing bolts = possible aftermarket clutch.

Just an idea...

[reficuliu]

Originally Posted by dyezak

Sounds like you may have purchased a previously modified car... And it was de-modded to trade it in. Those points were the bolts were missing/broken are all common bolts to touch when modifying the car. Missing downpipe support bolts = possible aftermarket downpipes before. Missing/broken transmission bellhousing bolts = possible aftermarket clutch.

Just an idea...

Hmm, that might be a possibility .. though from my understanding of the previous owner, its highly unlikely the car was heavily modded. Knowing the lifestyle of that person, i doubt there was that much time or interest in doing so to the car. . but regardless, i'm just glad the problem has finally been fixed

[kebinuu]

Thanks guys this post was most helpful to me.

After recent mods, turbo, downpipes and intake inlets.
I have this noise.
From around 1.8k till redline.

Gives me a lead!

[limitdown]

One of my 6AT's bolts broke. I didn't have any symptoms, but my Indy noticed it when he was doing something else down there.
If he didn't catch it, that might have led to more bolts breaking, shearing or loosening. I think this issue is quite rare. I would look at the other usual suspects first.

[JuniorB]

Just a good FYI,,it's always good to retap any bolts that are remover from the trans, or any other long bolt area and it cleans the treads and reassures you have nice then threads to start with. It your ever worried about bell housing bolt loosening up, I run steel bolts and nit the ends to the confines areas. It's piece of mind when your in there. A little neversieze gray will always help to stop corrosion. I would rather deal with threads that I can retap than broken bolts that are inaccessible. Loose bolts will damage the aliminum. Just my thought. It works for me .