R107, New Parts Kits and Manuals

I have a 1980 450sl and just replaced water pump thermostat and servo unit and catilytic converter and left and right side pipes. Runs gr8 but when i turn on a/c it starts out ice cold working well and blowing fine, but after about 5 to 10 mins it starts to blow heat. wondering if you might can tell me what to look for. tks MCTurner

My 88 500SL has recently started giving a Low Oil Level warning, usually after 20 minutes of motorway driving, but when checking the oil level, it's perfect! The oil and filter are less than 500 miles old, so my question is could there be a blockage in the oilways somewhere causing the sump to run dry. Has anybody else had this problem? Many thanks.