Hello all, at first, please excuse my very poor english !!! Since the early 90s I own a Camaro 1975, 350 ci, with factory A/C. At this time it was filled with R12. A few years later R413a was used (R12 no longer available in Europe), and years later R437a was filled, until now. The compressor (A6) is going leaky and I replaced it with a rebuild (A6). But the new one is filled with PAG150 compressor oil and therefore I "must" switch to R134a said the A/C Shop. After all was done, now the cooling is "weak !!! But I am doubt about the "filling amount" of R134a: Original R12 was 3lb. 12 oz. ( 1,700 kg in "european Units") as in the Camaro Drivers Handbook R413a and R437a amount filled at the shop was 1,600 kg ( About 94 percent of original) >>>>>>> And now R134a only 1,000 kg was filled !!! (nearly 60 percent ) <<<<<<<<< Why !?! What could be the reason for doing so ? Could it be cause the weak cooling ? Of course , I had to ask the People at the A/C Shop but I am very interested in the answers of the experts in the Forum. Thanks for your comments !