what is this noise?

[Mhutchman]

2017 x5 50i xdrive with just under 70k miles

Only happens when the car is cold started. Takes a few minutes then the noise starts. After the car warms up it stops.

Google drive link - no it isn’t a virus or pron.
https://drive.google.com/file/d/1M3W...w?usp=drivesdk

[stocktree]

That high pitch sound? Not sure

[Mhutchman]

Yep, that high pitched one

[shimmy23]

water impeller? i think they all kinda have this sound to a certain extent. yours may be a bit louder

[Clifton]

Any other details for things that you've tried?

Does the noise respond increase/decrease/constant to engine revs?
Which side of the engine is it more pronounced driver/pass?

Can you confirm it's a 5.0? Sounds like a diesel.

[Mhutchman]

Thanks folks.
It doesn’t happen all the time. So next time it does I’ll check the rev up. It’s. N63TU 4.4 v8.

I hear it most the front grill.

[tfunk88]

Jeez…that’s really loud. I’d try listening with the hood up and see if you can get a better idea

[Mhutchman]

So it doesn’t get louder when I hit the throttle. But the noise goes away when I open the oil fill cap.

[Clifton]

Originally Posted by Mhutchman

So it doesn’t get louder when I hit the throttle. But the noise goes away when I open the oil fill cap.

I would imagine that opening the oil fill cap would introduce a vacuum leak. Which may reduce the vacuum/pressure somewhere else.

Does the noise immediately return when you close the oil fill cap?

I would try taking the oil cap on/off until my ear could triangulate a smaller area for the source of the noise.

[Mhutchman]

It immediate goes away when open and comes back as soon as closed. The sound is coming from right behind the kidney grilles. Can’t tell more specifics than that.

[tfunk88]

So…this may not be it, and it may sound stupid, but…

When you remove the oil fill cap the noise goes away. I’m thinking that allows crankcase pressure to escape. You say if you put the cap back on the noise starts up again. And you hear the noise from just behind the grill. The PCV flows into the intake tubes, just behind the air box. And the air box has an intake just behind the front grill. I’m wondering if the sound is somehow coming from the PCV and emanating from the air box behind the grill?

[Mhutchman]

That’s something to check out. I can try and get the air box open when I hear it next and see if the noise is up in there.

Changing out the pcv’s on it doesn’t look too hard.

[tfunk88]

Originally Posted by Mhutchman

That’s something to check out. I can try and get the air box open when I hear it next and see if the noise is up in there.

Changing out the pcv’s on it doesn’t look too hard.

If you do end up changing the PCV lines just be careful. The plastic of the intake tubes gets brittle over time. The little elbows have a tendency to break off the tube. If only that happens it’s not that big a deal as they can be glued back on. But the elbow on mine actually broke apart in pieces when I pulled the PCV valve off. I didn’t care because I was venting to atmosphere anyway and plugging that hole, but just something to be careful of.

If you do need to replace the intake tube they’re each around $70 at FCP Euro

[Mhutchman]

Thanks for the heads up. Very very much appreciated. If I replace the pcv tubes it’ll be after the weather warms up. Pretty cold here in pittsburgh for another couple months.

I’m the mean time, I’ll try and get a better listen with the air box open.