Had local MB tech check low/high side pressure. Checks out. Getting 52 degree air at center vents at highway speed. If I exit the highway and drive around at say 25-35 mph, I soon see vent temps drop to 45 degrees.

Local tech indicated this could be the result of a long list. The car is 11 yrs. old and is equipped with orig. compressor, etc. - R12. Compressor seems to cycle often at highway speed. Suspected overcharging, but again, pressure check indicated all is well.

Serpentine belt is in good shape and properly adjusted.

I suspect an aging clutch and /or expansion valve.

Thoughts appreciated.

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