I have most of my AC system apart and made adapters and plugs so I can pressure test each component separately. My evaporator tested fine with no leaks so I am moving on to test other parts. One test I wanted to do was the output pressure of the compressor. I had the key on, and a piece of cardboard jamming closed the relay inside the Klima that turns on the compressor, and cranked the engine by jumping the terminal block.

I didn't expect the engine to start so fast and fumbled to shut it off with the stop lever. The gauge says "err" (error) when I shut engine off. Full scale is 1 MPa (145 psi) so it went above that.

Here's a video for a laugh
https://www.youtube.com/watch?v=9yWv2xqlZa8

I did this test at the discharge hose to the condenser, leaving the suction hose open.

Afterwards, I closed off the suction hose with an adapter and did a vacuum and pressure test. It held vacuum but failed pressure. I had R12 tracer in the compressor with 100 psi Argon and it was leaking at 0.14 psi every 2 seconds per the gauge. I wasn't able to find where the leak(s) is with the HF detector or Mega Bubbles. I'll be pulling the compressor and the hoses so they can be pressure tested alone.

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked