[SynAce]

So I just replaced the valve cover (aluminum), spark plugs & ignition coils (ngk 1-step colder), battery replaced, and vanos solenoids replaced by independent mechanic shop. Waiting on a tune (few days)

This noise happens when I brake or accelerate in park or drive. It’s only on the press of the pedal and not rpms and the sound is coming directly from the engine where the valve cover is. It’s pretty loud and if I press the brake once it’ll make the sound a few times, each time a little quieter.

[CalvinNismo]

Sounds like something is up with your vacuum setup, likely a leak. The vacuum ‘canister’ on the N55 is in the valve cover.

[SynAce]

Originally Posted by CalvinNismo

Sounds like something is up with your vacuum setup, likely a leak. The vacuum ‘canister’ on the N55 is in the valve cover.

Went to the shop and they said it was the diaphragm on the of the new valve cover. The size of the inlet is creating the sound. Mechanic told ne to get a new one.

[whyzee125]

Yup, PCV. Which brand did you go with?

[CalvinNismo]

Why would a noise whilst braking be the PCV? Or am I being stupid?

[wheela]

The brake booster pulls vacuum from the same pump as the wastegate/vac reservoir in the valve cover. If the valve cover has a crack under the vac reservoir, then vac could get pulled directly on the crankcase, bypassing the pcv valve. Since the brake booster is connected to the same vac source, perhaps using the brake changes the vacuum in the crank case (and therefore loading on the pcv diapgragm) (assuming there is a crack under the vac reservoir in his valve cover? I don't know, might be a long shot.

About the mechanic saying the size of the inlet is creating the sound - not sure I understand that. There shouldn't be any constant air flow through there, unless the diaphragm is torn.

Oh wait, I just realized OP said he has an aluminum valve cover, guessing that wouldn't have cracked? Any details on what valve cover you got?