How to Determine if your Audi is Actually Short of Refrigerant

DGraber460 at DGraber460 at
Sat Jul 5 21:52:34 PDT 2008

I have recently used the adapter on the "low pressure switch/port" under  the 
cowl cover in front of the windshield.
I unscrewed the switch, under which is  Shraeder valve (no system  emptying), 
and jumpered the sensor so the compressor would run. Started the car  and 
hooked the can to the port, quickly since the system was empty. The AC pipe  
immediately became cold.
Previously I had a friend with all the gauges etc fill the system the  
Bentley way which does work but requires a _lot_ of expensive equipment and  
patience. The system should be cold, vacuum evacuated, and the tank (not can) of  
refrigerant weighed _very_ accurately and heated so as to allow the refrigerant  
to flow into the non-running system via pressure differential alone. That 
method  did work but took several hours and I then found out I had a pressure leak 
that  did not show up under vacuum testing.
Therefore after replacing the seals, I tried the adapter and "cans" and it  
has been working beautifully for over 3 weeks now.

**************Gas prices getting you down? Search AOL Autos for 
fuel-efficient used cars.      (

More information about the quattro mailing list