[S1mon00]

Greatings!

Would you please help me diagnose this chirping noise coming from the engine bay: Video (noise starts at 00:07)

Details: 2011 335xi with 102,000km
Belt tentioner replaced at 92,000 km
Idler pulleys & belt have been replaced at 96,000 km
Charge pipe has just been replaced (VRSF)

Noise is not always present, only when engine is warm.

Many thanks!

[Pladi]

Originally Posted by S1mon00

Greatings!

Would you please help me diagnose this chirping noise coming from the engine bay: Video (noise starts at 00:07)

Details: 2011 335xi with 102,000km
Belt tentioner replaced at 92,000 km
Idler pulleys & belt have been replaced at 96,000 km
Charge pipe has just been replaced (VRSF)

Noise is not always present, only when engine is warm.

Many thanks!

I am at work and cant really play videos but first thing that comes to mind is the PCV system. Test it. It could be one of your main seals due to excessive pressure. Remove the oil fill cap while engine is on and warm see if the noise stops. If it does you have a bad PCV. When you remove the cap just keep in mind some oil might spew out have a towel ready.

[S1mon00]

Originally Posted by Pladi

Remove the oil fill cap while engine is on and warm see if the noise stops. If it does you have a bad PCV. When you remove the cap just keep in mind some oil might spew out have a towel ready.

Thanks, will give it a try.

Anybody recognise that noise?

[weehe126]

Wasn't very loud or long, but it does sound like a bad pcv. If it gets worse while coasting to a stop that would also confirm it.

[S1mon00]

Thanks for the input. Will do some test today and report back.

Potential culprit include:

• Front and rear main seal
• PCV system
• Alternator brushes
• Air conditioner compressor clutch
• Loose or rusty bolts in the pulley system
• Vanos

I definitively think it is pulley related as the noise is constant and "cycles" when crusing on the highway, is not present during iddle and becomes more audible when revving the engine while parked.

[S1mon00]

Okay so it's not the AC compressor. Noise does not go off when I remove the oil cap. Noise disappear when belts are wet.

If there are oil residue on the belt, is there a way to clean with dismounting it? It's a PITA reming these on xDrive.

[Mean E92]

You might need to do your pulleys again if oil leaked over them. I had this same issue. I did all my pulleys then oil leaked on them and it made the sound again. Check for leaks.

[S1mon00]

Thanks! In that case are the pulleys shot, or can I clean everything off and re-use?

[Mean E92]

Originally Posted by S1mon00

Thanks! In that case are the pulleys shot, or can I clean everything off and re-use?

If it is your pulleys than just get new ones and a new belt. If not, you will have a high risk of engine failure. It happened to me so I wouldn't want it to happen to you