This document discusses the symptoms of a clogged or bad radiator in a BMW X3. It lists several signs that the radiator may be clogged, including changed coolant, lower radiator hose issues, damaged radiator fins, increased engine temperature, and fluctuated coolant levels. The radiator is responsible for releasing heat from the coolant and a clogged radiator can cause overheating and engine damage. If an owner notices any of these symptoms, they are advised to consult a reputed mechanic to diagnose and fix the problem.