Hey, I haven't posted on these forums before, but I have been stalking them for awhile now. I have an 06 HHR LS that I bought via private sale a few months ago. I'm not sure if it has always been there, or if I am just noticing it now, but today when I was under the hood, I realised that there was a small hissing/air leaking sound. This noise starts as soon as the engine does, and will go on until I turn it off. After I shut the engine off it continues for 1-2 seconds, I hear a small "click", and then it stops. I used a small rubber tube as a makeshift "stethoscope" and pinpointed where the sound was coming from.



Right where the arrow points, under the black capped nozzle (?) and below the metal plate. I have always been the "get er done" kind of guy and am eager to learn, but I confess, I have no idea what these parts are, how to fix this, or even if there is a problem at all! Any input would be greatly appreciated.

 

Welcome to the site teknolla. That's a good question, I have gazed with wonder at that little dohicky my self. Can't say that I have heard that kinda sound from my 2.4, but it does make a few weird start up - shutdown noises. Want to hear something freaky start a 2.0..

 

Probably just the pressurized fuel you are hearing passing into the engine. The diagram seems to indicate the fuel rail pressure relief valve. If theres no fuel escaping, I think you are ok.

 

Thanks guys. There are no signs of any leaking fluids. I'm probably still just suffering from "oh no is something wrong with my new vehicle" anxiety.

 

Yeah odd noises at startup, plus that weird metallic sounding "thunk" 10 seconds after you turn it off. Throttle plate closing or whatever it is.

 

It is the fuel rai pressure release. It is a Schrader valve, I suppose your local GM dealer would be able to get you a new core fairly cheap, just release the pressurized fuel then use a tire stem core tool to R&R. Or, you might want to check that it is tight first. Just to see if it goes away.

I hesitate to say that the core may be identical to one you may find laying on the floor of any tire shop in the thousands, but.......maybe.

 

The sound seems to be coming from below the stem and metal plate, and not the valve stem itself.

 

Just for kix, you might check the torque on the intake bolts. The intake seals/gasket are basically rubber o-rings, so probably not a factor.