2013 Suburban LTZ Turbo like noise from driver vent / dash

[KevOLTZ]

Hey Everyone

I need some help here. I’m getting a strange noise upon acceleration/ start up coming from the driver side vent and or under the dash. It’s a hissing sound almost sounds like a vacuum leak under the dash inside the cab? I cut the AC belt and still there. No matter if climate control is on off or low or high it does not affect the noise and blower motor is fine. No noise when idling nor on the highway. Only at low speeds/ revving it in park and it almost mirrors what the RPMS are at. Attached is the video I uploaded via YouTube you can hear it even though may be faint

Thanks!

 

[donjetman]

Videos have to be loaded on youtube then post the link here.

 

[KevOLTZ]

^^

 

[mikez71]

Cannot hear it...

Maybe a leak in the brake booster?
I used to have one in a Toyota sequoia that would hiss until you hit the brakes..

 

[KevOLTZ]

Cannot hear it...

Maybe a leak in the brake booster?
I used to have one in a Toyota sequoia that would hiss until you hit the brakes..

That’s what I initially thought but preformed bleed down test and the booster seems to be working fine as well as the brakes themselves?

 

[mikez71]

Yea the leak wasn't big enough to affect the brake feel/function, but if you did a bleed down test it should be good.
Sorry I don't hear it in the video, sounds like passing traffic, don't even hear the engine running.
Maybe disconnect accessory belt to rule out any pulley/accessories...

 

[B-train]

I can hear something like you stated, and it does seem to follow RPM. I would do as @mikez71 said about the belt. Just take off the main drive belt on a cold start and see what you get. Is the PS fluid full? You could even pull the vacuum line off the booster and plug the line to eliminate that one as well.

 

[KevOLTZ]

I can hear something like you stated, and it does seem to follow RPM. I would do as @mikez71 said about the belt. Just take off the main drive belt on a cold start and see what you get. Is the PS fluid full? You could even pull the vacuum line off the booster and plug the line to eliminate that one as well.

Took it out earlier this morning and what’s odd is the noise is not present when it’s cold. Once the engine gets up to temp then the noise is there?

 

[Geotrash]

Sounds like you have a turbo on that thing. ;-)

I might suspect an intake manifold leak. Any codes being set?

 

[KevOLTZ]

Sounds like you have a turbo on that thing. ;-)

I might suspect an intake manifold leak. Any codes being set?

Sorry for the late reply, no codes (as of yet) I honestly have the gasket kit just have not had time to put it in