Performed one system tune up checking cooling. Checked inside units electrical and mechanical components, drain and filter all looked good. Checked outdoor units pressures amp draws and capacitor. Found that the system was low on Freon 2-4lbs. Homeowner stated that Freon has been added before. After seeing evaporator coil rusted pretty bad recommended warranting out evaporator coil. Homeowner wanted to apply for financing for repairs.