How to Change the Coolant in a 2018 Husqvarna FX450

Shop parts for a 2018 Husqvarna FX450 Dirt Bike.

Regular coolant changes are key to keeping your 2018 Husqvarna FX450 performing at its best. This maintenance task helps prevent overheating, protects key engine parts, and extends component life. Below, MotoSport.com breaks down the entire process so you can service your FX450's cooling system with confidence.

What You'll Need

  • New high-quality coolant (engine ice, or manufacturer-recommended)
  • Socket set
  • Drain pan
  • Funnel
  • Clean shop rags
  • Safety gloves and eyewear

Key Owner Notes for the 2018 FX450

  • The FX450 shares much of its cooling system with other KTM/Husqvarna off-road models, offering straightforward maintenance access.
  • Always allow the engine to fully cool before opening the radiator cap to avoid serious burns—the pressurized system can release scalding coolant if hot.
  • Use only silicate-free, phosphate-free coolant approved for aluminum engines to avoid corrosion inside the radiators and water pump.

Step-By-Step Coolant Change Instructions

  1. Preparation:
    • Put the bike on a stand and ensure it is stable and level.
    • Let the engine cool off completely if it's been running.
    • Remove the seat and side panels for easier access to the radiator and drain plug if needed.
  2. Draining the Old Coolant:
    • Place a drain pan under the right side of the engine (below the water pump area).
    • Slowly turn the radiator cap counterclockwise to release any residual pressure, then remove it entirely
    • Locate the coolant drain bolt–typically on the right side of the engine case, near the bottom of the water pump cover.
    • Remove the drain bolt using the appropriate socket or wrench. Allow the coolant to fully drain from the system. For a more complete flush, slightly tip the bike side to side.
  3. Flushing (Optional but Recommended):
    • If your coolant appears muddy, rusty, or contaminated, flush the system with distilled water–fill, run the engine for a minute, then drain completely. Repeat as desired.
  4. Reassembly:
    • Inspect and clean the drain bolt. Replace the sealing washer if damaged, then reinstall and tighten the drain bolt securely.
  5. Adding New Coolant:
    • With a funnel, slowly pour new coolant into the filler neck on the radiator. Fill up to the base of the filler neck or the top of the radiator cores (fins).
    • On the FX450, do not overfill–leave a small air gap to allow for coolant expansion during engine operation.
    • Reinstall the radiator cap by pressing down and turning clockwise until the release button locks in place.
  6. Air Bleeding and Final Check:
    • Start the engine, let it idle for several minutes, and gently rev a couple of times to help purge air from the system.
    • Shut off the engine and allow it to cool. Recheck the coolant level and top up if necessary.
    • Wipe up any spills and reinstall removed panels and the seat.

Safety & Environmental Reminders

  • Wear gloves and eyewear, as coolant can irritate skin and eyes. Rinse any splashes thoroughly with water and seek medical advice if needed.
  • Dispose of used coolant responsibly–do not pour into drains or onto the ground. Bring it to a recycling or hazardous waste facility.

2018 FX450 Model Considerations

  • The FX450's high-performance engine is sensitive to operating temperature. Using the right coolant and ensuring the system is bled of air bubbles is crucial for reliable long motos and spirited trail use.
  • If your FX450 is regularly ridden hard, inspect radiator hoses and the cap seal for wear–a small leak here will compromise cooling performance.

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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.