Generac — Cleaning the Cooling System

Maintenance

From a Generac service manual covering: CAC478, CAC480, SQR480. Check it applies to your exact model before use.

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Procedure

1. Drain the coolant and close the radiator drain plug or install the outlet hose.
2. Add clean water to the max water level of the expansion tank and install the pressure cap.
3. Start the engine, keep idling, warm to normal working temperature, then stop and cool down.
4. Drain the water.
5. Repeat steps until the drained water is as clean as the water added.
6. If cleaning is still required, drain coolant and remove the radiator outlet hose.
7. Insert the water supply hose into the radiator inlet and flush until water drained is clean.
8. Connect the water supply to the thermostat seat water outlet and wash the engine until water from the water pump inlet is clean.
9. If the radiator is very dirty, wash it from the reverse direction.

Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.

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