Blinkstang

So I have an 02' GT, that apparently thinks its a Cobra because it likes to hiss at me. When my car is idle or at a stop, it makes this on and off hissing sound. It could be happening when Im moving as well and I just do not hear it over driving noise.

Its coming from the engine, I opened the hood and its real loud when open. It hisses as I said, on and off. So like hiss hiss silence hiss hiss hiss silence. The silence is only like for a second or less. Is this normal or do I need to call animal control? My driving is normal and it does not seem to affect anything, so I thought it might just be a normal engine sound. But I do not remember having this sound on my previous 96' GT. Do I have an air leak of some sort? Thats what it basically sounds like, hissing air shooting out.

So what is it? Bad? What should I do?

Thanks guys!

Info:

2002 GT, Manual
No Engine Modifications (Yet...)
(Happens with A/C On or Off)

Guest

Sounds like either the radiator itself or a vacuum leak to me. Does it idle funny at all when it does it?

Blinkstang

No it pretty much idles the same, from what I have noticed it doesn't affect anything.

jdaniel

Sounds to me as though you have an exhaust leak.

Blinkstang

Would that noise come from the engine? I have the stock exhaust setup. How can I tell if it is?

4.6-GetBlown

I get the same noise in mine... I was just assuming that it was my MAM.

jdaniel

Yeap. It will sound as if its coming from a valve cover. If it gets bad then you will hear a ticking instead of a hiss. Its from your exhaust manifold(s).

josh_0351

My 02 GT does the same thing, but I'm not too concerned with it.

Acer2428

same.

josh4rim

Make sure you check the temp. of your car. Make sure it is not over heating. Also check for leaks in the intake or exhaust. Could be vacuum lines. Any thing that may suck or blow air. But the most common thing is leak in exhaust manifold or an over heating radiator if the car is idling normal.