90Bob

I finally got my ac fixed today. It hadnt been working for like 5 years and today i finally went to do a tuneup and asked the mech. to take a look at it(i though the radiator was gone, so i didnt wanna spend the 500-2k needed to get the thing working again). But all it ended up needing was some conversion and more freon. So i get the car back and after driving around i noticed that out from the passenger side air vent, there is some weird hissing sound. The ac seems to work fine. It makes a long hissing sound when u shut it down but the machanic said it was normal. But this sound that i now hear from the passenger vent is just plain irritating. If the ac works, do u think the problem is more related to the system not being put to use for so long? or something else needs fixing?

Thanks

Mr. fix-it

Mine hisses too. When you hit the recirc button it goes away. I have a new switch to try but I haven't done it yet.

Audi-90sGuy

Where it hisses but not constantly? The mechanic is correct in saying that when you turn off the car or the a/c you will get this long hiss. That is from the coolant evaporating in the evaporater. If it is a sparratic hiss(nothing that is on all the time) I have it as well while the a/c is on. My guess is that there is not enough coolant in the evaporator or at least a inconsistant flow to cause that hiss.
If you know how the system fully works it is easier to understand.

As long as your high/low pressure switches are working, you shouldnt need to worry about anything failing.

Eventually i'm going to get it recharged soon and see what it does after that.