[s-cars] AC low side recharge adapter...Update

[Tom Green]

Thanks for the personal experience update, Aaron.

This pretty much mirrors my experience with the adapter and the small  
recharge cans.  They don't seem to have enough pressure to discharge  
the entire contents
through the two schrader valves (one on the adapter gets depressed by  
the quick connect fitting on the can hose or gage set, the lower  
schrader that is on the car
system doesn't and depends on the gas pressure to force it down), and  
interferes with reading the low side with the gage set.

The folks that got them from me at //SFest got adapters that I  
modified with a 1/4" brass rod to depress the lower schrader when the  
adapter valve was actuated.
Removing the rubber bushing would do part of this too, and since the  
system fitting has an o-ring seal, this bushing is not needed.  This  
is certainly easier than
machining a rod to attach to the schrader in the adapter.  Pushing  
down on the quick disconnect did seem to help, but I had no issues  
with refrigerant escaping
from the QD connection or the can on the $18 special from flaps that  
has a reusable hose and gage and 19 oz refrigerant with some super  
cool addition that is
guaranteed to increase gas mileage and cooling by " up to 18 %  
".   :-)     Of course, most of the refrigerant is still in the can.

I used a gage set to check the high side pressure and monitor while  
adding freon.  With the high side only reaching 250 to 260 psi, the  
duct temp was down to
40 F and the low side pressure increased to 45 psi.  At that point,  
the small can would not discharge any more despite trying to keep it  
warm and vaporize
the refrigerant on this 95 F day.  The maximum high side pressure is  
290 psi but the duct temp with system on low, recirc, and rpm at 2K,  
stabilized at about the
lowest temperature obtainable from this system on these hot days.   
That will keep the car very comfortable, but it takes a while to get  
there, and just doesn't
make it on short trips.  By comparison, my avant got a new compressor  
(not rebuilt) last year, and after 3 recharge attempts to tweak the  
system, the pressures
and temperatures are almost identical to the 13 year old untouched  
system after my little addition.

If the high pressure is close to 250 or above I would be looking  
elsewhere for improvement, i.e. clean condenser and evaporator coils  
and ensure the flaps and
fans are all working properly.

The local flaps (Autozone) had gage sets that they charge a $100  
deposit and refund it when returned.  I had to clean it up first as  
it was left full of oil still under
pressure and dirty, but I have little desire to own a set of gages.

Tom  '95 S6
           '95.5 S6 avant

-----Original Message-----
> Date: Thu, 30 Aug 2007 20:27:53 -0700 (PDT)
> From: Aaron Ryba <aaronryba at yahoo.com>
> Subject: [s-cars] AC low side recharge adapter_Update
> To: s-car-list <s-car-list at audifans.com>
> Message-ID: <470536.50930.qm at web51405.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> So, thanks to Tom Green I recharged my S6 with R134a juice last  
> night and the AC now blows cold again (the first time for me)! Just  
> in time for the heat wave to be over.
>
> A little shout out here with my experience for those who have yet  
> to do this. Upon a recommendation by the local autoparts store I  
> purchased a can of the R134a premixed with oil and with a guage  
> installed in the filler line.  I don't recommend this because the  
> bottle started leaking a lot around where you depress the push  
> button trigger.
>
> Also, I had a hard time with the FJC adapter. It fit on the  
> pressure switch port fine but it seemed like the low side port  
> hookup wasn't depressing the internal schrader valve enough to get  
> pressure. Not sure if this was the crappy recharge tank I was using  
> or what but I eventually removed a rubber black bushing installed  
> on the inside of the adapter to fit it tighter and I had to  
> constantly push the low side port port hookup down onto the fitting  
> to get pressure. All in all it was a bit of a challenge to do all  
> this while shaking the can and having it leak noxious freon all  
> about the engine bay.  The original pressure was about 23 psi with  
> the car running, AC on max, pressure switch tripped. I was only  
> able to bring it up to about 25.5 psi or so even though the can  
> wasn't fully empty but that was enough to blow air at about 45-50  
> degrees from the vents.
>
> All said and done I would go for a higher qual. low pressure hookup  
> and a turn knob style refill can.
>
> Aaron Ryba
> 95 S6
> SC