I will be glad to answer that... and I am sure Jim agrees...
yes, you are probably looking at moving back to R12 in order , in Ariz , to have a nice cool working AC system... if the car AC had been engineered for R134a like new cars.. no.. but it was made to work with R12 and mostly in cooler climates... like Germany and Wisconsin..LOL

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1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/showthread.php?threadid=10414

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html