[Rayy_]

Hello guys, my car ( bmw 335xi 2008) started making this really high pitched sound recently and i don't know where it could be coming from. It reminds me of the sound my pulley(belt drive system) when it was due to change. So i changed the whole belt drive system not even 3 month ago. Also the sound is ONLY here when the car is cold, as soon as the oil it heats up it dissapears. I got told that it could be the idler pulley or the ac compressor but i looked it up and non of those make a sound similar to mine when they go wrong. Anyways, help would be great! btw it wouldnt let me upload the video using the "Attachements" section so i put it on vimeo. https://vimeo.com/614051201

[Serf27]

It’s a pulley or the belt.
Pull the belt off and see if it still squeaks.
I’d say the tensioner pulley.

[whyzee125]

You said you replaced the belt drive system but someone said it could be the idler.

Did you replace the 3 pulleys that you can get in the kit? Almost 100% sure one of those pulleys is your issue.

[Rayy_]

Originally Posted by whyzee125

You said you replaced the belt drive system but someone said it could be the idler.

Did you replace the 3 pulleys that you can get in the kit? Almost 100% sure one of those pulleys is your issue.

I ordered this and got my mechanic to install it, is this what you're talking about ? https://www.ecstuning.com/b-assemble...t/n54acbeltkt/

[Rayy_]

Originally Posted by Serf27

It’s a pulley or the belt.
Pull the belt off and see if it still squeaks.
I’d say the tensioner pulley.

So is it normal that the engine temperature affects weather a bad pulley makes a squeak or no?

[Serf27]

Well it’s not normal, but it happens.
I’m sure you’ve heard older cars squeak when they first start up.
It’s probably another pulley squeaking or the belt wasn’t changed.

[zomski101]

I had that sound when my oil filter housing gasket was leaking and dripping oil right onto the belt. Check for oil leaks and address asap.

[whyzee125]

Originally Posted by Rayy_

So is it normal that the engine temperature affects weather a bad pulley makes a squeak or no?

Yes. Both of my cars that had bad pulleys only squeaked when cold. Sounded perfect when warmed up.

[whyzee125]

Originally Posted by Rayy_

I ordered this and got my mechanic to install it, is this what you're talking about ? https://www.ecstuning.com/b-assemble...t/n54acbeltkt/

Yes. If all those are replaced, that's weird. Possible that your OFHG is leaking onto them or it could be your fan squeaking.

[Rayy_]

Originally Posted by whyzee125

Yes. If all those are replaced, that's weird. Possible that your OFHG is leaking onto them or it could be your fan squeaking.

i mean i do have a leak from the valve cover gasket, could that be it?

[whyzee125]

Originally Posted by Rayy_

i mean i do have a leak from the valve cover gasket, could that be it?

Yes could be leaking onto the belt