Arrived to find (2) systems in home Turned both to cool to find downstairs with decent temp split Upstairs unit has a bad temp split and checked Freon pressures to find additive dye injected into system which I do not recommend due to possibility of gumming up valves and metering devices. Found upstairs system low on Freon and is reasoning for system over working. Found leak in evaporator coil and recommend replacement . Downstairs system is 20 years of age and do not recommend putting money into system if breaks down.