Hey all,

Just did VANOS seals, anti-rattle rings, also rebuilt DISA valve on my M54... I'm still hearing funny noises from the engine bay... Any thoughts as to what it could be?


Definitely sounds accessory driven. Is there a way to test my water pump, or diagnose/troubleshoot the noise?

Car is a 2004 525i 154k miles

 

Have you check to make sure it was not a pulley going out? It could be the pump. If it has not been changed with 154K on the dash then it is over due.

 

What do you mean pulley is going out... as in the pulley fails? Like cracks?

I'm not sure of the previous maintenance history and if it has been replaced before.

Thoughts on how to test?

 

Bearings in pulleys go bad and create noises. You can look at each one to see if you see wobbling. Start at the belt tensioner since those fail mostly first. The easiest way to test is take the belt off and turn each one to see if you get the same noise. It sounds like it was coming from the general area you were filming

 

Bearing Design

The water pump pulley is not a bearing design

 

Use a mechanic's stethoscope. They're cheap and no toolbox is complete without one.

Probe behind the pulley with the engine running to isolate the noise. Be careful and don't get entangled in any moving parts.

 

to me it sounds more like the bearing in your alternator


If you can pull the font belt and spin each pully by hand you will soon find the problem bearing or pully to replace


The old mechanic trick is to put a long screwdriver onto the body of the alternator and then your ear to the opposite end of the screwdriver


you will be able to hear the bearing noise if it is that

 

+1 with the alternator. I am not there at the car but it sounded like it was coming from the belt tensioner or alternator (it definitely seems like its coming from that corner. The pump seems like its fine.