1994 525i

Hi: Iam up in the air what to do with my BMW,always seem to have air in coolant,have bleed before,occurs again, it now looks like i might have water in my engine oil,possibly bad head gasket,also my fan motor i s really noisy,only works on high,was not blowing heat before, bleed again and filled with coolant now blows some heat, don't know if its worth fixing i can do it myself if i get some guidance, if i know the extent of everything, if not may sell for someone to project!

if it has a combustion leak, put a used engine, engine not worth fixing.

Thanks, it may seem a used engine not worth it either, may just sell!!