[Mullins]

Hey all, who's up for another round of WTF is that noise?!

I've been hearing this sound for a while now, it's typically always noticeable when i pull into my garage, after the car is warmed up. I always notice it when I come to a stop, and put it in Park (I do that towards the end of the clip), but you can hear it as I begin to apply gas every time. When it sounds like it's chattering, thats me tryin to just hold it in the range where it makes the noise.

I want to say it something like an actuator, perhaps the throttle body? I can also hear it under acceleration while driving, but its harder to capture.

Adding a second video which it's much more repeatable. I was able to replicate the noise easily when in Drive and holding the brake pedal while lightly applying the gas. You can hear the sound every time, and when i let off the gas, it sounds like the actuator "resets" or something. I need to see if I can do this while my wife is in the car, and I have the hood open...

Any ideas?


Edit:

Well, after opening the hood and having my wife put it in drive and apply the gas (sounds super safe, right?), i think I may have the culprit. I think the belt tensioner might be making the noise? Aside from the noise, it seems pretty wobbly when under load? Ive seen a few replacement suggestion for wobble, but I've never seen a mention of a noise like this. Anyone seen/heard this before? Hard to tell for sure...

[GarrettM235i]

Experiencing a similar noise. Mine is much quieter. Just a slight metallic chirp/grind under mild throttle only. Just as I press the pedal and a similar but slightly different noise just as I let off. Hard to hear at high speeds but I hear it cruising through the neighborhood in third gear. Thinking it's possibly a sticky waste gate actuator. Not sure. Will keep up to date.

[BrandonMllr]

The sound really throttle.

[Mullins]

Added a second video which I'm able to reliably repeat the noise.

[The_otherM235i]

Fan turning on maybe?

[Mullins]

Posted an update, I think it may be the belt tensioner, but its hard to say for sure. I only have 35k miles on the car, seems a bit early for something like this to go out?

[khj24]

Sounds like a bad pulley bearing to me

[Mullins]

Well, I swapped the tensioner and the idler pulley with the kit from FCP and the noise appears to be gone. Neither of the wheels appeared to be grinding at all, and seemed in good health but hard to tell when not under pressure. Consider this solved...