well over the weekend, i recharged the ac system on the blazer and so far it has cured my no ac problem. now when i go to shut off the truck or turn off the ac, i hear a hissing noise coming from the silver canister or the high pressure hose underneath it. it will hiss for about 20 seconds or so then stop. it does not sound like an external leak and i did not feel anything blowing on my hand but then again that hard to feel. i put a charge into it yesterday and the ac is still blowing ice cold, so i do not think it has a leak. is the hissing normal or do i really have a leak?

 

Hmm... when I turn my AC to off or Max, normal, and air to face and feet, it also hisses. Mine only hisses for about a second after, but it interests me too.

 

It is likely the pressure equalizing through the orifice tube. You may have a restricted orifice tube. Bad thing is you have to evacuate the system to check and/or replace this.

 

yea that could be. i know that when my grandma had it she never really used the ac, and has not been in use in the past 2 years. im sure that isnt the greatest for it haha

 

As long as the ac is working then I wouldn't worry about it... I have had several vehicles that have done this for a few seconds after shutting off and otherwise worked normally.

 

My 2001 blazer also does this^ like he stated on the qoute. I recharged it about a year ago and ac still blows cold no probloms