I had the radiator replaced with the recommended BEHR radiator, with the reinforced hose neck (the original one didn't come with one) back in 1999, and R12. The charge for the radiator, at the MB dealer in San Rafael Calif. was $332. The air conditioning still blows cold. When it works, which isnt every time. Maybe I need a monovalve now, not gotten to it yet...
Someone here mentioned, if I recall correctly, that the R134 air conditioning isn't quite effective as the OEM set up.
As a matter of fact, many parts - catalytic converters, mufflers, replacement batteries, and the like are often best done with the MB parts from the dealer or a good MB parts outfit like fastlane or
www.epsparts.com
A professional fix with genuine MB parts gives the best result and peace of mind, in my opinion.
But there may be a better and cheaper way. I don't know for certain
GOOD LUCK.
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1991 560 SEC AMG, 199k <---- 300 hp 10:1 ECE euro HV ...
1995 E 420, 170k "The Red Plum" (sold)
2015 BMW 535i xdrive awd
Stage 1 DINAN, 6k, <----364 hp
1967 Mercury Cougar, 49k
2013 Jaguar XF, 20k <----340 hp Supercharged, All Wheel Drive

(sold)