I use Castrol 20-50W motor oil in all of my Alfas. The most difficult thing about changing oil in a 750/101 is the cartridge oil filter. I always use a new gasket for the cartridge oil filter and once in a while would have big oil leaks. I even bent the cartridge oil filter bolt and had to replace it. I would probably tell you to have your oil changed by an Alfa mechanic or someone who knows about Alfas. I always change the oil when the engine is cold because I have been burned by hot oil or a hot oil filter more than once. The oil drains slowly, but I always wait until the oil slowly drips from the oil pan. I have driven and worked on Alfas since 1968. I have rebuilt twelve engines and ten of those were Alfa engines. I like to change oil every 3,000 miles.