DTB S-B-01.20/24 FEB09 ML63, C63, CLK63, E63, CL63, CLS63, S63, SL63, and R63 up to engine # 156698x 60 022000 - whistling sound from the engine compartment (in the area of the firewall) the cause may be a malfunctioning diaphragm in the pressure-regulating valve. The sound can also be heard for up to several seconds after the engine is switched off. The sound goes away when the engine dipstick is removed. To resolve, the valve is replaced.

thanks for the info, my ML63 is making the same whistling sound.
I guess i should have the mechanics at my mercedes dealership check out this forum, so far they've replace a breather pipe & a v belt....they may come back and tell me another story tomorrow. I will see what they say next!

I new it!
Im not going crazy
I hear it every morning afternoon and evening when i start the truck.
I have heard it since day 1 of buying the truck.

Is it an intricate job? ive already had the prv replaced. Towed from Monrovia in 100 degree heat. What a blast that was.
Should i bring the truck in ......na ill compile a few things and then bring it in. Like the rubber grommets on the running boars on the drivers side are all chewed up. like if i was wearing baseball cleats to jump in the car or something. oops!

thanks for the heads up!

hi
just like 2 know id that whistling noise affects the performance off the car

i had it along with a CEL. they said the code was for leaking intake manifold. The prv valve (not really a valve but for a lack of a better term...) the job is a pain in the a$$ with intake manifold on so they replaced it while they were repairing the manifold leak. The whistling sound is now gone.

other than a tiny oil leak, i doubt there is any performance issues associated with it.

I hear that after i close and lock the car, but i think its more to do with the AirMatic personally. As it coincides with the car lowering. A very brief whistle release of air.

I has the same valve on my old 740iL BMW (M62- 4.4L). When this valve tore (its kinda a bladder), man the car was WAY down on power, and it would BELLOW smoke.

I feel that the whistle in mine, is definitely associated with the AirMatic settling.

This is normal Sir... Same on my car, when you lock your ml the car lower itself so it looks better, such a cool feature

Thats why my ml63 nickname is Bumblebee

Remove the belt and start engine. If noise goes away, then it is coming from one of the pulleys on the accessories, thus eliminating a vacuum leak on the engine.

Happened to my truck replaced the valve and alls well

Good Morning,
Hello everyone, my name is Santiago, I have the problem of the whistle to resentí in the engine, by the zone of the intake manifold.
The engine is a 156, which valve is the one that needs to be changed? Is possible photo or reference?
Thank you very much

Pcv valve, sits on the back of the motor. Not an overly expensive part but a pain in the *** to replace. Made out of plastic they seem to crack over time and are quite common on the m156 and make that distinctive whistle.

Thank you very much
I am trying to upload some photos to confirm that the valve but I am not able. How to do it?

In the end I managed to upload the photos !! Hahaha
Is this valve failing ?? I have a video of the whistle, I'll try to upload it ..

This is the whistle
https://*******/photos/UuLPRREsmobsYBYe9

This could help:
https://mbworld.org/forums/ml55-amg-...k-popping.html