Air hiss coming from engine

[2013 Geee T]

I'm starting to notice an air hissing sound coming from my engine when I start it in the morning. I can even hear it from inside the car. It sounds like its coming from around the plenum/throttle body area but I haven't tried to pinpoint it yet. If I give it gas it affects the sound. I'm pretty sure once it warms up it either goes away or is not as loud. It seems to be louder when its colder. Any ideas?

 

[timeless2]

Any vacuum hoses disconnected? Check for punctures as well. As rubber heats up, it swells and could partially seal up the fissure. When it's cold, the gap is wider due to contraction of the material ==> louder sound.

 

[2013 Geee T]

Thats what I was thinking. Ill have to get in there and dig a little deeper. It seemed to have started shortly after doing the plugs so maybe something got bumped loose.

 

[SilverBullet00]

Mine has done that since I bought it. I have never been able to find the source

let us know if you find anything!

 

[RandyStinchcomb]

another common problem: check the PCV hose going from the PCV valve to the plenum, very common problem lately on 2002 to 2004 Gt's

 

[2013 Geee T]

Where exactly is the PCV valve on these cars? I looked for it but couldnt find it unless its hidden or looks like something else.

 

[RandyStinchcomb]

Where exactly is the PCV valve on these cars? I looked for it but couldnt find it unless its hidden or looks like something else.

middle of the rightside cam cover

 

[2013 Geee T]

As in passenger side?

 

[RandyStinchcomb]

As in passenger side?

correct passenger side = right side..........driver side = left side

 

[Mike97gt]

If it is not the PCV hose or any other hose check the PCV valve itself. If that don't fix it try this.

WHILE IT"S MAKING THE NOISE

While holding the TB slightly open and unplug the IAC if the noise goes away then it is the IAC valve. they nornally don't make a hissing noise they make this strange air vibration noise I really can not describe

 

[2013 Geee T]

I replaced the IAC valve about 4 months ago but Ill check it out.

 

[2013 Geee T]

All I see on the cam cover in the middle is a hose with an electrical connection attached to whatever its plugged into. Its right under the air intake tube. Is that it?

 

[blckstng96]

take a can of carb cleaner and while the car is running spray it around hoses and the unpper intake and stuff.do this all one thing at a time.if the idle changes you have found your leak.mine did the same thing.happened to be the unpper intake manifold.on the under side of it where it meets the throttlebody there was some sort of factory plug.that plug worked its way outon its own.try that