Re: AC

[Mike Loeks <neanderthal@ardvark.com>]

At 07:14 PM 4/25/96 -0500, you wrote:
>
>Regarding removing the existing refrigerant and trapped air:
>
>I was at the repair shop today and the coolant was down 1.5 lbs (1lb
>remaining). They added 1.5 lbs and were unable to find any leaks. Is the
>refrigerant under pressure or does air come in when the refrigerant leaks out?
>
>michael
>
Michael, 
  Yes the refrigerant is under pressure.  Anywhere from about 60 psi on the
low side to about 300 or so psi on the high side. Can't remember exact
numbers right off hand.  Air will only enter the system if there is enough
of a leak where the pressure in the system bleeds off to atmosphere.  There
are a couple of reasons to make sure the air is evacuated from the system
before recharging with freon.
These are the ones I know of and there may be more.

1. Air does not respond the same way as freon when it goes through the
system      thus reducing the efficiency.

2. Air usually means moisture which is very bad in an air cond. system.
Moisture can freeze in the orifice in the evaporator coil and clog the
system.  It can also cause rust in the a/c system.  This is why it is a good
idea to replace the receiver/drier when the system has been open.

On the 5k's the schrader valves are hidden under switches, so they are not
obvious like on other cars I have worked on. Don't know about other Audis
however.

Just my .02 
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               Michael Loeks
               '86 5kcstq - Red w/ Fuchs wheels 1.8 bar boost
               '86 5kcstq - Grey w/ 1.8 bar boost
               '84 Ford F350 dually flatbed(NOW we're talking utility)
               Warren, Oregon


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