Vehicle described below in signature. Odometer reads 133K. Original Nippondenso R-12 compressor and R-12 refrigerant.

Until recently, have seen vent temps in the 42F-45F range in 95F - 100F ambient temps. Cooling was good.

Now seeing 60F-65F vent temps. Sight glass is cloudy. Suspected low charge. Hooked up gauges, but readings do not reflect a low charge, at least according to my interpretation of information presented in tech manual mentioned below.

Low Side = 40
High Side = 200

Gauge readings taken inside garage - ambient temp in garage = 95F. Fan set to high - clutch engages - compressor remains on - not cycling off.

I'm referencing Mastercool Automotive Air Conditioning Basic Service Training Manual. I see situations close to, but not quite in line with mine. My current suspicion is the expansion valve is stuck - either closed or open. Not sure at this point.

Knowledgeable opinions welcome.

Thanks for your time.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"