Liquid-cooled Guardian generator displays LOW COOLANT LEVEL or COOLANT LOW and may not start.

Safety first: Turn the controller to OFF, open the main breaker, and allow the engine to cool completely before opening the cooling system.

• Check coolant reservoir: Inspect the overflow bottle and radiator for proper coolant level. Add the correct coolant mixture if low.
• Inspect for leaks: Look for dried coolant residue or wet spots around hoses, clamps, water pump, and radiator core. Tighten clamps and replace damaged hoses.
• Check level sensor: Verify the coolant level sensor connector is secure. If the sensor body is cracked or corroded, replace it.
• Bleed air (if required): Follow Guardian procedures to bleed air from the cooling system after refilling.
• Reset and test: Clear the alarm and run the generator while monitoring for leaks and proper temperature.