Hi all. Slowly continuing to work my way around my '90 735i. Noticing that there appears to be a bit of a high pitched sound to the engine, and I'm not quite sure if it's normal/what it would be related to. Hard to tell exactly where it's coming from other than it does not appear to be from the belts/pulleys. I recall years ago that my '90 535i had a similar tone to the engine at idle. Here's a video of the engine at idle in hopes that the sound comes across clearly: https://youtu.be/NSVC4KoGK4c Any ideas on what might be going on appreciated!
I would check your tensioner and pulley bearings. It's usually just a 10mm and 13mm if I remember right to loosen it up. Feel for any play in it. Sounds like a metal on metal type whine.
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Thanks. I imagine they should be pretty solid, and I should not be able to move them by hand when the belts are on? Maybe the sound is just resonating oddly, but it does not seem to be coming from the front of the engine...hard to tell.
**update** Using a stethoscope, the sound seems to be loudest at the intake manifold, right around where the "3.5L" writing is. I don't really hear it at the head or the block or anywhere else. I suppose it could still be a pulley resonating weirdly... Any additional thoughts appreciated. Again, I remember hearing a similar pitched sound on my old '90 535i years ago...hoping someone here has heard the same and determined the cause. Thanks!
Last edited by schnell944; 07-14-2018 at 04:23 PM.
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