Hello, I have an 07 Silverado 5.3l. I recently installed a 57 3058 K and N intake and when I shut the engine off I hear a short hissing or puff. (Sounds like it could be a relief valve, only lasts a second or so) I have not heard this before, is this normal?

Thanks
Lee

 

Yes. It is normal.

 

not sure how long that it makes that sound? The only thing I can think of is the A/C high and low are balacing the pressure out. if the a/c is on when you shut the truck off the lines have to equal the pressure out.

 

It makes the noise when the AC is not on. However with the climate control system is seems like the AC is working even if the fan is not on and the display is not lit.

 

Yes it is normal, mine does the same thing (97' 1500)