If you need your AC unit for one more season can you change the outside AC compressor from a 3.5 to a 4 ton unit without changing the air handler?

When you have a larger outdoor unit than your indoor unit, several things come into play. Some units are ARI rated as in the capacity loss, efficiency loss, ect. It is not a good idea. Also, evry time you put a new outdoor condenser into a system, it has a full oil charge. When you add the oil alraeady there, you have too much. I do not know if you were meaning a new unit or one that still works just to get by. With the cost of operation, you are always better to replace the system new with matching components.