After sitting parked for a week, the a/c on my '93 infiniti g20 is
completely dead.  It blows warm.  The high and low pressure lines are
the same temperature - fairly hot.

My question is regarding the sight glass.  I wouldn't describe what
occurs as foamy.  It looks more like there is just 1 drop of liquid
visible, clinging to the glass.  It's visible and stationary with the
compressor off, and it starts to jump around with the compressor on.

Would this indicate an extremely low R-12 condition?

Thanks a lot.