Car still whistles with serpentine belt off (however didn't take the AC belt off). But the fact that dipstick out / open oil cap stops the noise leads me to believe that it's not belt-related... Or can it still be AC belt?

Do you mean the y-pipe for the air pump?



Thanks for the input guys!

 

Use to have e46 that did that and it was one of the pulleys. Change idle pulley and .......cant remember which other one. Went away. My e60 starting to do that now. Guess its time to change this one too

 

skunky
Not the pulley/tensioner. However I still have to remove AC belt and check the compressor.

Quick update:
Sometimes the noise stops exactly when the air pump shuts off. That exact second. Don't think it can be a coincidence. But it only stops with the air pump like 20% of the time. All the other times it continues for another ~15-20 seconds. Maybe the valve is sticking...

 

Hi
Did you ever fix the noise?
I am having this issue and its frustrating! My car whistles, and I get the check engine light with code P0507.
I checked the crankcase valves and they are both very clean and intact. No tears. Dont know if I should replace anyways. I feel if they have no tears replacing would be throwing time and money away.
Did you solve this problem?

 

I don't think you have the same problem. The noise I have is weather-dependent.

Start with your code first and fix it. Maybe you have a vacuum leak, which would explain the noise and the code.

 

To ensure air pump is not the culprit, simply disconnect the power source from the pump before a cold start. If the noise is gone, it is the pump or the related plumbing.

 

Thanks. I've pulled out the fuse for the AP and the noise was still there. Also turned on AP with DIS when the engine was off, no noise.
It's not directly related the the air pump, but maybe a secondary air valve is sticking and it creates it...

 

Hi RTR,
Did you ever figure out what was the cause for the Whistling Noise at Cold Start? Got the same exact symptoms like yours on a 2006 550i

Thanks,
seahawk