I would check it all out and change everything you can't flush (or replace it if you don't want to flush). Its almost impossible to flush condensers and the orifice tube (liquid line). The manifold line could probably be flushed. Remember to get some extra PAG 100 oil if needed, its 6.1 oz for a complete fill on the 01 XJ (earlier models, not sure when it started, spec'd 8 oz).