vibration at idle

bigxO · 10-31-2024, 10:04 PM

I’ve been noticing a vibration in my 328i E90 (N51 engine) for a while, and it seems to be gradually worsening. The vibration is only present when the car is idling—whether I’m at a stoplight or in park—and it disappears as soon as I start driving or increase the RPMs.

I suspect it might be related to the motor mounts or transmission mount, but I haven’t done any inspections or diagnostics yet. What could be causing this, and what’s the best approach to identify and fix the issue?

Phil325i · Yesterday, 03:36 AM

If it's motor mounts, open the hood and watch the behavior of the engine when you blip the throttle. If the mounts are shot, the engine will rock side to side.

bigxO · Yesterday, 07:00 PM

I’ll give that a try and see if there’s any movement when I blip the throttle. If the engine does rock side to side, is there a specific way to check which mount (or mounts) might be the culprit? I might just end up replacing all the engine mounts and the transmission mount since I’ll already be in there, if that’s the issue. Also, any recommendations on replacement mounts? I want to make sure I get ones that will last or be better.

10-31-2024, 10:04 PM	#1
bigxO Registered 0 Rep 7 Posts Drives: 2011 BMW 328i Join Date: Aug 2024 Location: memphis, TN iTrader: (0)	vibration at idle I’ve been noticing a vibration in my 328i E90 (N51 engine) for a while, and it seems to be gradually worsening. The vibration is only present when the car is idling—whether I’m at a stoplight or in park—and it disappears as soon as I start driving or increase the RPMs. I suspect it might be related to the motor mounts or transmission mount, but I haven’t done any inspections or diagnostics yet. What could be causing this, and what’s the best approach to identify and fix the issue?
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Yesterday, 03:36 AM	#2
Phil325i Brigadier General 636 Rep 3,209 Posts Drives: E92 325i MSport Coupe Join Date: Apr 2012 Location: UK South East iTrader: (1) Garage List 2009 BMW 325i Coupe [6.00]	If it's motor mounts, open the hood and watch the behavior of the engine when you blip the throttle. If the mounts are shot, the engine will rock side to side. __________________ E92 pre-LCI 325i - Ohlins R&T; H&R spacers; M3 strut brace; Swift thrust sheets; 3 x chassis braces; diff brace; N53 V-brace; 034 subframe inserts; BMS clutch stop; BMS CDV; RE g/box mounts; Delrin shift bushes; Saikoumichi OCC; Cyba scoops; BMW Perf Exhaust; HEL s/steel brake hoses; M3 rear spoiler; Recaro Sportster CSs; M3 white dash LEDs; LED Angels; LED side repeaters; BMW Perf black grille; CSL reps; SSDD carbon diffuser; Monster Wrap black roof/clear front
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Yesterday, 07:00 PM	#3
bigxO Registered 0 Rep 7 Posts Drives: 2011 BMW 328i Join Date: Aug 2024 Location: memphis, TN iTrader: (0)	I’ll give that a try and see if there’s any movement when I blip the throttle. If the engine does rock side to side, is there a specific way to check which mount (or mounts) might be the culprit? I might just end up replacing all the engine mounts and the transmission mount since I’ll already be in there, if that’s the issue. Also, any recommendations on replacement mounts? I want to make sure I get ones that will last or be better.
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