Performed ac tune up on Goodman ac unit. Check electrical low and high voltage connections and components. Air filter ok. Check supply and return air temps ok. Flush drain add tabs to pan. Inspect indoor coils. Check outdoor units refrigerant refrigeration levels and pressures capacitor and contactor ok. Cycle ac unit ok. Joe and I looked at one radiator not getting hot. After troubleshooting came to conclusion to replace radiator. We have tried everything else. Joe will create estimate for new radiator.