How to Change the Coolant in a 2021 Sherco 450 SEF FACTORY

Shop parts for a 2021 Sherco 450 SEF FACTORY Dirt Bike.

The 2021 Sherco 450 SEF FACTORY is built for both longevity and peak performance, making regular coolant changes essential for the health of the engine and the entire cooling system. This unique model uses a closed-loop liquid cooling setup with specific requirements for high-temp operation, so always use the recommended coolant and follow these model-specific steps carefully.

What You Need

  • Motul Motocool Factory Line -35°C coolant or a high-quality equivalent approved for aluminum engines
  • Ratcheting wrench with metric sockets and Phillips screwdriver
  • Drain pan
  • Clean funnel
  • Shop towels or rags
  • Gloves and eye protection

Step-by-Step Coolant Change Procedure

  1. Prepare the Bike
    Place the Sherco 450 SEF FACTORY on a stable, level surface using a paddock stand. Ensure the engine is completely cool before you proceed to avoid burns and pressure spray from hot coolant.
  2. Access and Drain the Cooling System
    • Locate the radiator cap on the left radiator. Slowly twist it off to relieve system pressure.
    • Put your drain pan below the water pump area (near the lowest point of the cooling system).
    • Remove the coolant drain bolt from the water pump cover. On the 2021 450 SEF FACTORY, this is typically an M6 bolt (refer to your bike's diagram if unsure).
    • Let the old coolant fully drain into the pan. Open the bleed (purge) screw on the left radiator to help air escape and ensure complete drainage.
  3. Flush (Optional/–Recommended for old, dirty coolant)
    If the drained coolant looks contaminated, pour a small amount of distilled water into the radiator and let it flow through, draining again. Repeat this once or twice for maximum cleanliness.
  4. Reinstall the Drain Bolt
    Install the drain bolt and tighten to 6 Nm. Double-check for a good seal. If the bolt uses a crush washer, inspect or replace it as needed.
  5. Refill the Cooling System
    • Use a funnel and slowly pour fresh Motul Motocool or approved coolant into the radiator filler neck until the liquid is level with the internal neck.
    • Wait briefly and check if the coolant level drops as air bubbles are purged. Add more coolant as necessary until it stays at the correct level.
    • Reinstall the bleed/purge screw on the left radiator.
  6. Bleeding the System
    • Start the bike and let it idle with the radiator cap off. As the engine warms, air will rise and escape. Occasionally squeeze the upper radiator hose to assist removal of trapped air.
    • As the coolant drops, top off as needed.
    • Once no more bubbles appear, turn off the engine and fill to the neck if necessary.
    • Install and secure the radiator cap.
  7. Check the Expansion Tank
    Locate the reservoir (expansion bottle), and make sure the coolant is at the LEVEL mark. Top off if needed.
  8. Clean Up & Final Inspection
    • Clean up any spilled coolant. Run the engine briefly to confirm there are no leaks and check the level once the engine cools again.
    • Dispose of used coolant responsibly at a recycling or collection facility. Never pour into drains or onto the ground.

Important Model Notes for Your Sherco 450 SEF FACTORY

  • This model requires coolant designed for aluminum engine components to avoid corrosion—never use plain water or non-approved fluids.
  • The 2021 Sherco 450 SEF FACTORY uses a precisely tuned closed cooling system. Monitor the coolant level regularly, especially after hard use or in hot climates.
  • Replace coolant at least every two years, or sooner if riding in harsh or muddy conditions.
  • If you spot coolant leaks (especially at the weep hole), inspect the water pump seal—a common issue that can lead to engine overheating if ignored.

Taking care of your coolant not only preserves engine performance, but also extends the life of your 2021 Sherco 450 SEF FACTORY, letting you focus on the ride instead of repairs.

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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.