On arrival system was running and not cooling. Found a piston metering device inside with an older indoor unit and a 3 year old outdoor unit. Found compressor only pulling 7.8 amps in the direct sun at 97 degrees outside. Compressor rla is 16.7. Superheat was 0 with a low side saturated temp of 80 and a line temp of 80. Hot gas discharge temp was 99. System appears to have plenty of refriybut the compressor is mechanically failed. Recommended replacing full system so if something like this happens again it will have a full 10 yr warranty. Will follow up with customer on Wednesday to discuss sending a comfort advisor out.