Even if the R134 conversion was done correctly (sensors, schraeder valve, etc.), it may not cool a big car like yours in your climate. A friend of mine with a 560SEL is adding a second condensor to get his system to work better.

With that said, does the air blow colder right after the engine is started? That would indicate that hot water is getting into the heater core, or that the flaps are not moving into the "cool" position.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe