Ray,

Converting a R12 to R134a is definitely a mistake. I don't think the Midas guys can fully understand the AC operation in your MB. As Steve said you need to find a mechanic who really knows MB AC system.

Since you can get cool air when ambient temperature is down. I am suspecting the recirculation flap get failed thus the outside hot air get mixed with the cool air.

I am not familiar with 85 380SE. I'd recommed you take some time to search this site for a clue.

Sorry for not being help.

Charles from Taiwan

94 C220 AMG style