97 Tahoe whistling

[Mark97]

Hi!
New forum member here. I hope this is in the right spot.

1997 Tahoe LT 5.7 gas vortec engine.
Last night it just started a really high pitched whistling.
All the time at idle.
When I accelerate, it goes away.
If I'm cruising, it whistles.
It only stops when I accelerate.
No noticeable difference in idle or performance at any speed.

It seems to be loudest on the passenger side of the engine compartment. Other than that, I got nothing.

Any ideas?

Thanks,
Mark

 

[GreyStone]

Hi!
New forum member here. I hope this is in the right spot.

1997 Tahoe LT 5.7 gas vortec engine.
Last night it just started a really high pitched whistling.
All the time at idle.
When I accelerate, it goes away.
If I'm cruising, it whistles.
It only stops when I accelerate.
No noticeable difference in idle or performance at any speed.

It seems to be loudest on the passenger side of the engine compartment. Other than that, I got nothing.

Any ideas?

Thanks,
Mark

check the pcv valve

 

[OR VietVet]

Welcome to the forum from Oregon. Sounds like a vacuum leak but that loud of a leak should cause a running problem. May be a squealing belt, check that. Does it make a difference whether it is in gear when accel or not? An inexpensive mechanic's stethoscope would pin it down quick.



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[Mark97]

The only time the whistle goes away is when I accelerate. No other difference in performance or behavior.

Took off the pcv valve. Cleaned it up. It still rattled freely. Put it back on.


I still have the whistle.

 

[OR VietVet]

Something that loud and distinctive should be easy to pin down.

 

[Danny3737]

Sorry, couldn’t resist

 

[96-2D-Hoe]

Heater control valve solonoid?
Does the AC on or off make a difference?

Gonna have to narrow it down some.

 

[OR VietVet]

Heater control valve solonoid?
Does the AC on or off make a difference?

Gonna have to narrow it down some.

He said the noise was on the passenger side so this could be it. Do the heater and a/c controls work and do the blend doors all move to correct position?

 

[96-2D-Hoe]

There's not a lot of vacuum on the passenger side.

Air intake housing and engine breather are all else I can think might whistle on that side.

 

[PG01]

It whistles because it doesn’t know the words.....

If it goes away when you accelerate.... well you know what to do then....

seriously now, look under passenger side dash, should be some vacuum lines for hvac controls... make sure everything is pushed together... pretty sure that year stil had the clear connector with all diff colored vacuum lines going to it, no?