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High and Low side pressures not within specs

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    High and Low side pressures not within specs

    Hello everyone, have this case of 2001 VW Jetta. Vehicle had an evaporator leak, however customer never replace it and kept it like that for about 5 or 6 years. So the A/C has never been used for that long. Last week customer decided to replace the evaporator along with the expansion valve.
    4 ounces of pag oil were added to system due to evaporator replacement, vacuum was applied, vacuum hold test was run, small charge of R134 was applied in order to check for leaks at the expansion valve, everything was ok.

    Next, full charge of 750 grams of R-134 was applied, static pressures were 80-90 PSI on both sides with A/C compressor off and 85 degrees ambient temperature.
    A/C compressor ON, both condensor fans running and A/C compressor clutch engaged, no compressor noise that indicates any internal failure or bad bearing.

    However, pressure readings were odd, high pressure side only reads 120 PSI and low pressure side 65 PSI when compressor clutch engages. No on/off fast cycling switching at the compressor, it always ran steady without interruption.

    Since expansion valve was replaced because I suspected it could be stuck due to the long time this A/C system was not used at all, when I get this readings it makes me think that the A/C Compressor seals are done due to cracking or seizure and because the only cause why this A/C system stopped working was due to evaporator leak and not a compressor failure I believe A/C compressor needs to be replaced.
    Any opinions will be welcomed.

    Thanks in advance

    Al Martin
    Last edited by Al Martin; 02-09-2021, 05:16 PM.

    I may be wrong but I believe that uses a variable displacement compressor. Your symptoms are a classic of a system stuck in the low displacement. There should be a valve in the compressor that can be replaced.
    Something like this:
    2001 VOLKSWAGEN JETTA 2.0L L4 A/C Compressor Control Valve | RockAuto


      It seams to be a real common problem in VW's of that vintage. I've not dealt with one myself, so don't know how difficult the valve is to change. Obviously a compressor change would achieve the same result at much more cost.