Idler pulley misalignment

Rogejo321 · 07-29-2023, 11:43 AM

Hello Everyone - I have a new to me 2011 335i xDrive (N55) that I’ve been pugging away at in terms of a few repairs. I noticed that the serpentine belt seems to be hitting the edge of the harmonic damper. I pasted a picture below of the belt drive and circled in red where it’s hitting for reference.

I figured that replacing the tensioner and idler pulleys might solve the problem so just finished that up. Unfortunately, it’s still hitting with the new pulleys. It looks to me that the large idler pulley is potentially misaligned so the belt is walking off that pulley slightly. I was wondering if anyone has ever run into this issue before? And if so, is there a straightforward way to adjust that pulley alignment? Any help would be very appreciated!

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zeezul · 08-03-2023, 06:51 AM

Did you get this figured out? I have a 2011 335xi n55 e90 and a 2007 335i n54. I haven't come across anything like this and I've replaced the belts, pulley's and tensioners on both cars. Maybe the tensioner is misaligned somehow but why wouldn't the belt be off track on the other pulleys and not just that one? I would focus on that pulley that it's not lining up right with or the pulley that it's coming off of. Were you having any symptoms? Good luck!

07-29-2023, 11:43 AM	#1
Rogejo321 Registered 0 Rep 2 Posts Drives: GTi Join Date: Jan 2019 Location: NYC iTrader: (0)	Idler pulley misalignment - Need Help Hello Everyone - I have a new to me 2011 335i xDrive (N55) that I’ve been pugging away at in terms of a few repairs. I noticed that the serpentine belt seems to be hitting the edge of the harmonic damper. I pasted a picture below of the belt drive and circled in red where it’s hitting for reference. I figured that replacing the tensioner and idler pulleys might solve the problem so just finished that up. Unfortunately, it’s still hitting with the new pulleys. It looks to me that the large idler pulley is potentially misaligned so the belt is walking off that pulley slightly. I was wondering if anyone has ever run into this issue before? And if so, is there a straightforward way to adjust that pulley alignment? Any help would be very appreciated! View post on imgur.com Last edited by Rogejo321; 07-29-2023 at 11:47 AM.. Reason: Embedding picture link
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08-03-2023, 06:51 AM	#2
zeezul New Member 2 Rep 21 Posts Drives: 335i Coupe Join Date: Mar 2015 Location: United States iTrader: (0) Garage List 2011 335xi [0.00]	Did you get this figured out? I have a 2011 335xi n55 e90 and a 2007 335i n54. I haven't come across anything like this and I've replaced the belts, pulley's and tensioners on both cars. Maybe the tensioner is misaligned somehow but why wouldn't the belt be off track on the other pulleys and not just that one? I would focus on that pulley that it's not lining up right with or the pulley that it's coming off of. Were you having any symptoms? Good luck!
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