On the 190E the A/C evaporator is under the hood & takes 3 hrs or less to replace.
All Behr OE evaporators are ALUMINUM!! only sone of the less $$ aftermarket parts are copper!
R134a doesn't melt any glue holding the pipes but will erode Aluminum.
THERE aren't any OE R134A componets on the W201(190) chassis, however the replacement Driers & Expansions valves are for R134a or R12.
On the aftermarket evaporators that I've installed on 190's bending(tubing) slightly is REQUIRED. But they work well!
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)