Replaced alternator and pulleys twice and still hearing crickets on cold starts

[Epsilon]

I had a major refresh with new water pump, new OE pulleys, and new Valero alternator. 4K miles later, the squeaking sounds that sounds like crickets chirping came back. Replaced the idler pulley and alternator and the squeaking noise became less annoying but is creeping back again. Fortunately, I bought everything from FCP, but curious why this keeps happening. The noise origin sounds like it's occurring where the alternator area is.

Attaching sound clip here.

Any ideas?

[oceansize]

You sure it isn’t the dme fan? Can sound like crickets.

Edit: After listening to the clip probably not the dme fan.

[jet_dogg]

You replaced both idlers 6 and 14? Belt?

https://www.realoem.com/bmw/enUS/sho...diagId=11_2998

[Epsilon]

You replaced both idlers 6 and 14? Belt?

https://www.realoem.com/bmw/enUS/sho...diagId=11_2998

Replaced #14 twice. #6 came as part of of this kit which I've replaced just once but may try again.

[FBloggs]

That sounds like a pulley.
It's got the grainy sound of dry ball bearings.
what brands did you get?

[Epsilon]

That sounds like a pulley.
It's got the grainy sound of dry ball bearings.
what brands did you get?

Used all the OE brands from FCP which is INA for the pulleys. Everything was new and my trusty mechanic installed everything for me. Perhaps, just bad luck?

[sapote]

the squeaking sounds that sounds like crickets chirping came back.

It sounds like belt tried to climb off the water pump pulley due to misalignment. Use a straight edge and lay it on the WP pulley face and use it to check if the belt is a few millimeters off the tensioner pulley (to much forward at the tensioner as compared to WP pulley).

[old///MFanatic]

Sounds like a belt.
Does it subside after the first start of day?

[JamesSJ1]

Following. I currently have 93k miles, and have had a chirping sound on cold starts since ~50k miles. Replaced a couple pulleys and and both belts, tensioner. Your squeak is pretty consistent, more like the belt or a larger pulley rubbing on something at every revolution. Mine is more of an intermittent squeak, and it goes away within 10-20 seconds of starting, which has me believing mine is the water pump / water pump bearing getting some lubrication and then the sound goes away.

[sapote]

Mine is more of an intermittent squeak, and it goes away within 10-20 seconds of starting, which has me believing mine is the water pump / water pump bearing getting some lubrication and then the sound goes away..

Yours could be a belt noise too; as the rubber got warmer from rubbing belt and pulley side guard, it got softer and the noise gone.

[DropTopKingM3]

Definitely the DME fan.

Read the description in the ecs link. You have to get the correct one for your car. Ie: 6mt or smg. Same thing happened with me. I replaced pulleys and belts twice over the past 10 years and I still had the crickets sound.

https://www.ecstuning.com/b-genuine-bmw-parts/blower-motor-control-module/12907571019/

[old///MFanatic]

He has the recording outside the car at the front foglight. Having replaced the ECU fan on a couple M3s I worked on this does not sound like it. He also states it’s a cold start issue. The ECU fan would not trigger that long at cold start imho.