How to Fix / Troubleshooting

Safety first: Do not open the radiator cap on a hot engine. Allow the generator to cool completely.

Steps:

Check coolant level: Inspect the overflow reservoir and radiator (when cool). Add the specified coolant mixture if low.
Inspect for leaks: Look for dried coolant residue or wet spots around hoses, water pump, radiator, and engine block.
Sensor check: Locate the coolant level sensor in the radiator or tank. Inspect wiring and connector. Clean contacts and reseat.
Pressure test (pro): If coolant loss is suspected, have the system pressure-tested to locate leaks.
Clear alarm: After restoring proper level and fixing leaks, clear the Low Coolant alarm and run a test.

On liquid-cooled Honeywell standby generators, controller displays 'Low Coolant' and prevents operation.

Possible Causes