hello members,
i am new here, I just joined to seek help before I proceed to spend money, I bought this car with 95,000MILES, drives fine so far but there some issues with car,
Car info: Type PG77 | Model 323i U1 | Development Code E90 (MUE) | year 2011 SEDAN
Metal plate sound coming from bottom side, it only comes intermittently, its not happening permanently. Please listen to audio file.
https://vocaroo.com/i/s0PJKewGTPjA
Thank you
Last edited by adm1n1strator; 03-20-2019 at 09:04 PM. Reason: updated info
Get under there and poke around.
Are you gonna eat that?
Your best option is to get it up on a lift and observe where exactly the sound is originating from.
If I were to guess, I would say a loose catalytic converter heat shield.
Properties of noise
- its like spoon hitting another utensil , please listen to audio link
- it only comes intermittently, its not happening permanently.
- Does not come when driving fast/accelerating car like above 40-45mph.
- Comes always when idling or on slower speeds.
After diagnosing, looks like its coming from somewhere near Alternator, below alternator, or around alternator. Not sure about that, but the area for noise source is somewhere there.
I have tried following with my mechanic:
1. Remove belt and only run engine alone, nothing connected to engine with belt and NOISE is GONE.
2. Connect belt and noise came back.
3. Replaced Idle pulley today and noise is still there.
4. Check thoroughly under the car and exhaust as well and all is good below and with exhaust too.
5. Alternator has 14.5v output, I am not sure if its alternator making that noise, I cant take risk for changing alternator, its too costly to just try.
Please help me.
| Model 323i U1 | Year 2011 SEDAN | Development Code E90 (MUE) | Type PG77 | Miles 95000
That didn't sound like an internal engine noise, so if the noise really is something related to the belt, it seems like it would have to be the belt tensioner itself (not the pulley). And it appears that the tensioner is right next to the alternator. Maybe the belt has stretched to the point where a failing tensioner contacts something when it bounces during operation.
I found a video from youtube which I can say matches my car,
Only difference between my car noise and this youtube video noise is very bad
My noise is soft and this guy's car noise is way too bad.
https://www.youtube.com/watch?v=R3pzV2Bb8Xo
Last edited by adm1n1strator; 04-02-2019 at 12:40 PM.
| Model 323i U1 | Year 2011 SEDAN | Development Code E90 (MUE) | Type PG77 | Miles 95000
With the belt off,and engine off also,
attempt to spin by hand, every pulley that belt normally contacts.
Listen for noise and feel for bearing smoothness.
Or just one of the two idler pulleys?
Are you gonna eat that?
yes, I changed this part
https://www.ebay.com/itm/For-BMW-OEM...-/361179958292
thanks
- - - Updated - - -
I found that sounds goes away above 1700 RPM when idle or driving. It comes back below those RPMs
| Model 323i U1 | Year 2011 SEDAN | Development Code E90 (MUE) | Type PG77 | Miles 95000
Did you check the crankshaft vibration dampener when you had the belt off?
I still think the noise is coming from the tensioner, but it could be caused by backlash of the belt due to a bad dampener. The engine smoothes out naturally at higher RPM.
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