Loud hissing noise - vacuum leak?

[ksanders]

Hi, I have some problems with my Mazda Tribute 2005 (2.3 L, manual transmission). Every morning when I get stuck in traffic, after about 15 minutes I get a loud hissing sound. Whenever I accelerate, the sound gets weaker and eventually stops, but as soon as I release my foot from the gas pedal or drive at constant speed, the sound comes back. When I open the hood, it's very loud and sounds like a vacuum leak, I'm having a very hard time to locate the source of that sound. My guess is that it's coming from a lower part of the motor and the sound I hear is bouncing from everywhere. I played with the different hoses I have access to, just to see if that could make the sound vary, but I still could not locate it.

I brought my car to a (very bad) car mechanic and he told me it was coming from the alternator strap. He changed it and, of course, that didn't fix the problem. Before going back to see him, I'd like to find the root cause so that he doesn't spend an hour looking for it (or even better, so that I can fix it myself).

Any help would be greatly appreciated.

Thanks,

Kari

 

[ksanders]

News from a new mechanic today. The source of the noise is the tube that connects to the PCV valve. The tube itself isn't very expensive, but they apparently need to take apart part of the intake, which will cost around 500$. Since it's just coming from a small hole in the tube, isn't it possible to just patch it with strong epoxy?

 

[destineal]

Can you see the hole or access it without removing the intake? Intake manifold or just the intake? Personally, I wouldn't pay $500 to replace a hose, but that's just me. I would put a piece of tape over the hole and hit it with some liquid duct tape a few times. the hose is old though and could benefit from a good replacing.