Whooshing / "Fwooo..." noise when releasing throttle under load?

[kageryu]

Morning all,

We recently got back from a trip up into the mountains that involved a full car and lots of climbing. As we were climbing the hills, a strange noise started coming from under the hood whenever we let off the gas (to slow for a turn or traffic, etc). It almost sounds like a owl's hoot, and decreases in pitch and volume as the engine spins down. My suspicions are with some kind of bearing, an air or vacuum leak of some kind, or the gremlin of a transmission that's mounted on our T6 [cussing]

Unfortunately, I can't get it to replicate at idle... it only happens once the engine is warmed up and is climbing a hill, and even then not consistently enough that I think it will happen for my service guys.

Any ideas?

[AF330i]

We had the same exact noise when our vehicle was new (it is a 2004 XC90 T6) and when I took it in then they said it was normal though there was a fix so if you go to the dealer, they should know what yourt talking about.

It has something to do with the intake ...

[Zig]

Sounds like the waste gates operating on the turbos.

[dmd]

From what I recall, there was some issue with one of the turbo tubes on the T6
that would do this. Not a major issue, just need to replace the tube, or just leave
it and know what the noise is.

[thebracko]

From what I recall, there was some issue with one of the turbo tubes on the T6
that would do this. Not a major issue, just need to replace the tube, or just leave
it and know what the noise is.

Agreed. It sounds like one of the plastic tubes has split at a seam.

[kageryu]

Got the new ducting installed as per the service bulletin, haven't noticed it since....