Need help with belt drive e46 | The Car Community | Page 1

tidal echo Mar 17, 2025, 9:09 PM

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Hello! Lately Ive been having issues with the belt drive on my 2001 325i, Originally the issue was my idler pulley went bad, which led to me sporadically losing power and a loud whining noise. Since then I replaced the belt tensioner (i swapped it to a mechanical tensioner, it was previously hydraulic) I also replaced the idler pulley. The loud whining noise is gone, however there is still a slight quiet whistle and there is a rattling from the belt drive which I am not sure is normal or not. Please help me diagnose!

spice ingot Mar 18, 2025, 6:19 PM

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tidal echo Hello! Lately Ive been having issues with the belt drive on my 2001 325i, Origin...

Where is your power steering pump?

tidal echo Mar 18, 2025, 6:33 PM

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spice ingot Where is your power steering pump?

spice ingot Mar 18, 2025, 6:42 PM

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Whistle slightly sounds like the power steering pump. Which isn’t too far fetched. You probably didn’t hear the noise before because it was whining.

balmy cedar Mar 18, 2025, 7:58 PM

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By chance - were both tensioners replaced?

tidal echo Mar 20, 2025, 1:13 AM

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balmy cedar By chance - were both tensioners replaced?

On the serpentine belt drive yes, not on the ac belt side though

tired garnetBOT Mar 20, 2025, 1:13 AM

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GG @tidal echo, you just advanced to level 4! Chat more to level up and earn top roles!

tidal echo Mar 20, 2025, 1:13 AM

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I replaced the serpentine belt idler pulley and tensioner

spice ingot Mar 20, 2025, 1:49 AM

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Only way to know really is to perform a process of elimination.

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I would remove the serpentine belt and run the car for a minute or so and see if you hear the noise.

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If you still do, then remove the AC belt. Then you will know what belt is driving the noise and go from there.

#Need help with belt drive e46