Summer is approaching, and my A/C is not working. So, I just attempted to recharge my system. Here is my story:
- got dual gauge manifold, checked system pressure, 0 psi on high side, 5 psi on low side.
- evacuated tiny bit of remaining refrigerant from low side
- attached low side to vacuum pump and and vacuumed for 30 minutes
- closed lines, shut off vacuum and let sit for 1 hour to see if vacuum held; it did.
- Vacuumed for another hour to get as much moisture out of the system as possible, AC has not worked for a while as far as I know, I bought the car in September 2017 and it was on the list of problems in the PPI.
- Closed lines, turned off vacuum, attached refrigerant to yellow service line, opened refrigerant, purged air from line, opened low side line, and psi on lowside increased to 30.
- started the engine, turned on ac, and examined compressor. it was engaging intermittently for about a minute, then engaged continuously.
- pressure on low side climbed to 45 psi, but never dropped when compressor engaged. High side pressure rose very slowly to about 50 psi, then neither pressure really increased after that.
- compressor engaged, but ac still blowing warm. Had to leave, so I took the car for a drive, keeping the AC on. Noticed a loud hissing sound in the dash and immediately turned the AC off.

Does anyone know what this could be? It's like theres a blockage between the low pressure side and high pressure side, or the compressor just isn't pulling the gas through.
I will note that engine was cold when I began this procedure.