Can anyone help pinpoint this weird sound?

[Crazy Dave]

E36 sound from lower end

After doing an overhaul on the cooling system, while bleeding it I heard this weird noise. It may have been there before this, but I didn't notice it until now. I'm on a quest to just replace things before they fail as I go, but trying to fix what's necessary first. This one has me baffled. Oil was changed 2 weeks ago, and looks fine from the dipstick. Car is a 97 328i with 114k on it.

[Eric93se]

Probably one of the idler or tensioner pullies is bad, usually if they are original then replace all of them.

[Crazy Dave]

Probably one of the idler or tensioner pullies is bad, usually if they are original then replace all of them.

They're original. The bolt on the tensioner pulley was pretty rusty looking. Replacing everything else, might as well replace those.

[mitch500]

Remove the serpentine belt and start the car for 20 seconds or so. If the noise isn't present anymore then you know it's a pulley or accessory and can diagnose into those areas.

If the sound is still present then it's coming from the engine.


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[gc325is]

if it is the same as this sound... try pouring water on the fan clutch area and it will go away. However it is temporary and will return after a while but then it will also go away when hot.

https://www.bimmerforums.com/forum/s...-is-this-sound

[doclees]

My idler bearings made more of a squealing when bad. A friends harmonic balance sounded like that as did another's fan clutch.