With that being said then yes that is where the hiss is from and no will not hurt anything

 

As long as its on the positive side and not the negative side, you should be fine.

 

by negative side you mean the turbo side that sends the air into the intercooler? How would I be able to tell a difference? Obviously in this case I know since the broken gasket in the first place leads me to believe that gasket is the culprit....

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Well, sorry for nother double post....but Im pretty convinced now that its this gasket and I am going to wait till it comes in and see if that stops the hissing. If anyone has any further input please add it thought. Back to the original post, that shutter the truck did after it first started, could that be from the silicone? Could I have done any harm by using permatex RTV on that intake horn/grid heater instead of the factory gasket??

 

Negative side is the air intake into the turbo. Positive side is the air that has been compressed by the turbo.

 

Oh ok thanks for the info...could there have been any downside to using RTV to seal it? And is there a possibility I could have an exhaust leak? I dont hear the air noise at idle, just as teh RPMS move up

 

No boost at idel.

 

if the silicone was too cold when you put it together it could have not sealed good. also did you clean the horn of ALL oils? if not theres your leak.

 

Ok....replaced that gasket...and still I hear the hissing from what sounds like through the defrost vents....I am about to install my boost gauge just to see what my numbers are at...Could it be an exhaust leak? I woud think I would see soot all under the hood if it was. I went down the road and layed a few thick clouds then checked for soot under the hood...nada...I checked all the clamps and they are tight on the boots. I KNOW I have a vacuum leak from somewhere because when I do turn on the ac or heat it only blows from defrost...is it possible that the vacuum leak would cause that sucking sound as RPMs increase?

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Or could it be the actual intake gasket between the head and the horn?

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Or I just thought of this too.....the heat barely worked when I bought the truck two weeks ago..could it be coincidental that the heater core started making nouse? Will heater cores make an in cab hissing like that?

 

Take care of that vacuum leak and see if the hissing noise is still there. Process of elimination is the best way to find issues.

 

Well turns out I had more vacuum leaks then I thought but Im tracing them down and too kcare of some today...while i was digging around in there guess what I found....a bolt that my buddy and I forgot to put back in..the bolt that the holds down the injector lines on the intake plenum....I called him and it was sittin on his toolbox...leak solved!