Engine crickets

[arisonford]

so about two weeks ago i began to hear a strange whistling noise coming from my car. i describe it to people as a fluttering cricket's chirp. it occurs most often when i let off the throttle at about 2500 rpm, either in gear or neutrel. sometimes its impossible to hear, and occasionaly it can be heard over the engine while im on throttle. i didn't notice any real performance drop off, but it had to be fixed regardless.

I confirmed that there is a noise with the SA and he confirmed with a tech. i left the car (a toyota higlander as the loaner?!?!) and the next day they called and told me it was a crack in the vacuum canister and the part had to be ordered. the next day i picked it up, new canister and all, and its still there.

My issues: 1.Does ANYONE else have the cricket??? 2.if this is just a noise the engine makes, then why did the find a crack in the canister and replace it. 3. if it is specific to my car, why would the change a part that seems to be unrelated to the problem, either way, i dont like it....

[Swift135]

If it sounds like a can of spray paint being shaken then its the same reason that my car was updated to V30.2 software. Its the waste gates vibrating as they open and close as you get on and off the gas.

[arisonford]

Not so much like a paint can. its more of fluttering chirp.

update from bmw, they said its normal. i asked to hear it on another N54 engine and they let me listen to a brand new 335. the noise was barely (i mean barely)audible, but did exist somewhat. they said as the engine gains miles the noise gets louder. i dont buy it, the noise ruins the engine note at all but WOT driving. the shop forman said its from the wastegates not being completely closed or open at part throttle...does anyone have this problem???

i love the car, but would not have bought it knowing that fixing imperfections is avoided as long as its not harmful to the car.

[JKAWB]

It sounds like part throttle boost to me, pretty common on turbo cars with small turbos at low rpm's when you let off the accelerator.

[F0Bman]

Broken Vacuum canister does make that noise all the time. Good thing bad vacuum doesn't affect performance.

[Vancity1]

Originally Posted by JKAWB

It sounds like part throttle boost to me, pretty common on turbo cars with small turbos at low rpm's when you let off the accelerator.

this is exactly what it is btw. It's why you have linear turbo boost and a car that goes like stink.