a/c issues

[William Magliocco]

Based on your earlier postings:

1)  What you are reading with your gauge apppears to be HIGH SIDE pressure.  When operating, the low side pressure should be much lower.  R134A would have an optimal low side pressure around 30 PSI.

2)  If the fitting you are attaching to on the car is on the coil that is in front of your radiator, and the first thing that incoming air would "touch", you would be looking at pressures on the DISCHARGE side of the system, the high pressure side.  That coil is the CONDNESER coil.

3)  You should have two "pipes" with refrigerant entering the passenger compartment that are adjacent to each other.  The smaller one is the higher pressure one of the two, the larger one is the "suction" line which would go back to the compressor with a minimum of other parts in line.  This is where you measure the low pressure, on the SUCTION side. So follow the fat pipe 'round. 

4)  I have a 1993 Audi 100.  The HP fitting is on the condensor coil; the LP (suction) fitting is on the compressor.  You might have to unwrap some insulating material to see it, that's what I had to do.

5)  The little gauge you are using is a LOW PRESSURE SIDE gauge.  All consumer gauges of this sort are designed to be LOW PRESSURE side gauges.  Based on the color coding it is meant for R134A applications.  I own professional gauges as well as a couple of the consumer types too.

5)  Maybe I missed it, but what kind of refrigerant is in use?  A 1990 Audi would have been equipped with R12, but a retrofit could have been done.  

6)  What type of fitting do you have on the condenser?  does the hose end push on with a locking collar?  If so, that means it is an R134A fitting.  R134A fittings are size coded-the larger ones are on the LOW PRESSURE side.  

R12 fittings were threaded.  I have seen them on VAG products be the same size and also two different sizes.

It is mandatory to add "permanent" fitting adaptors when converting to R134A from R12.

WPM-EPA section 609 permit holder...though that does not make one an A/C whiz kid.