Listen to this strange noise! Noise when engine stopped. (SOLVED)

[ltemup4650]

All, I have a strange noise when I stop the engine. 2011 X5 with N55 engine.

It sounds like an animal squealing/yelping in pain. It is not the belt (I removed it and started/stopped the engine and the noise didn't go away). Listen to this craziness. What do you think it is? I hope this YouTube link works:

https://youtu.be/a7VdpSW0xYM

[ard]

Yup. You've got kitten in the left intake.

[andrewwynn]

Sounds very belt squeaky. I would start/stop the car with the serp belt off and see if it goes away then it's a matter of finding which load has a less than perfect mate with the belt, also check the belt for telltale signs of odd wear

[ltemup4650]

Originally Posted by andrewwynn

Sounds very belt squeaky. I would start/stop the car with the serp belt off and see if it goes away then it's a matter of finding which load has a less than perfect mate with the belt, also check the belt for telltale signs of odd wear

Andrew. You didn't read my original post. Belt was removed and engine started/stopped without it.

[andrewwynn]

Yep sure did miss that. Try with the car in gear I'm suspecting engine mount. It sounds like a rubber flexing through steel. Engine mount, control arm bushing or the like. Not sure what would move enough without torque on the motor it sure is an puzzle.

Try also to wiggle the motor, spin the cooling fan. Does your motor have a mechanical cooling fan?

Listen with mechanic stethoscope and pin down what quadrants of the motor.

[ard]

in all seriousness... air being pulled through a slit in a rubber air hose/duct might give such a sound. Maybe it is being pulled when motor is running, and there is enough flow it makes no sound... but once the air flow drops, the slit partially closes and you get the sound?


Just WAGing here....

[ltemup4650]

All, thanks for your comments. I'm 99% sure it is the PCV valve. Here is why:

I put in some seafoam into the oil to clean the system before I change the oil here soon. After doing that, it ran really strange, surging idle and even stalling a couple times. AND, when I shut it off now, it continues to run a little (like old cars "diesel"). It is obviously pulling in oil fumes into the intake and with the high VOC seafoam now in the oil, it continues to run. Only way that could happen it with a malfunctioning PCV system. So, the noise coupled with what I just discovered = PCV valve in my opinion.

Just watched other YouTube videos of N55 PCV failure and they are the exact same noise. I'll be replacing the whole valve cover.

[FREE100KSECRET]

Change it out and your problem will be gone.

[Cyrix2k]

I also agree with it being the CCV. My e46 does the same thing except it sounds like a dying wookie.

[ltemup4650]

I replaced the valve cover. Noise is gone as well as the "dieseling" / run-on after shut off. Thanks everyone.