Controller displays AL02 / High Engine Temperature and generator shuts down during load

Safety first: Turn OFF the generator, open the main breaker, disconnect battery negative, and allow the engine to cool completely. Never open the radiator cap on a hot engine.

• Check coolant level: Once cool, remove the radiator cap on the Kohler-SDMO canopy-mounted radiator or check the expansion tank. Top up with the specified coolant mixture if low. Inspect for external leaks at hoses, water pump, and radiator core.
• Inspect radiator and airflow: Remove debris, dust, or plastic bags from the radiator fins and air intake grilles. Clean fins gently with low-pressure air from the engine side outwards.
• Verify fan operation: On engine start, confirm the radiator fan (belt-driven or electric) runs and pulls air through the radiator. Check fan belt tension and condition; replace worn or slipping belts.
• Check thermostat: If the engine overheats quickly despite good coolant level and airflow, the thermostat may be stuck closed. Remove and test in hot water or replace with a Kohler-SDMO specified thermostat.
• Reset alarm: After corrections, reconnect the battery, clear AL02 on the controller, and run the generator under light load while monitoring temperature.

If overheating persists, internal coolant passage blockage or head gasket issues may exist—contact a service technician.