The inside coil was not replaced when the current outside compressor was installed in 2007 and it wasn't a warranty stipulation then. It did subsequently develop a leak and was replaced about five years ago, which is why I thought it might be worth saving.You probably can, but I think the internal coil often isn't terribly expensive and on a older install might be wise to do. Possible too, it might be a warranty stipulation too if you're buying a new outside unit.