How to Change the Coolant in a 2015 Husqvarna FC450HQ

Shop parts for a 2015 Husqvarna FC450HQ Dirt Bike.

If you ride a 2015 Husqvarna FC450HQ, keeping the cooling system in top condition is essential for reliable race performance and long engine life. Regular coolant changes prevent overheating and reduce corrosion in the radiator and engine passages. This guide from MotoSport will walk you step-by-step through the proprietary process for replacing the coolant on your motocross machine, and it also highlights key points unique to the FC450HQ model.

Preparation – What You Need

  • High-quality motorcycle coolant (never mix incompatible coolants; use what the manufacturer recommends or a trusted performance coolant)
  • Distilled water (for flushing, if required)
  • Drain pan
  • Basic tools: socket set, screwdriver, torque wrench, and pliers
  • Clean rag
  • Protective gloves

Step 1 – Allow the Engine to Cool

Your FC450HQ's engine and exhaust reach extremely high temperatures during operation. Always make sure the motorcycle is completely cool before you work on the cooling system to avoid injury and ensure accurate coolant levels.

Step 2 – Access and Prepare the Radiator

  • Place your Husqvarna FC450HQ securely on a stand so it's upright and level.
  • Remove the right side panel to access the radiator cap.
  • Loosen, but do not remove, the radiator cap to release pressure in the system.

Step 3 – Drain the Old Coolant

  • Position a drain pan under the water pump area.
  • The FC450HQ features a coolant drain bolt on or near the water pump cover. Locate and carefully remove this bolt.
  • Allow all existing coolant to drain fully. Tilting the bike gently from side to side can help clear pockets of coolant trapped in the system.
  • If preferred, reinstall the drain bolt and flush the system with distilled water to remove any old coolant residue. Repeat until the drained water runs clear.

Step 4 – Inspect and Reinstall

  • Check the condition of all hoses, clamps, and the drain bolt washer. Replace anything that shows signs of wear, cracking, or corrosion.
  • Reinstall the drain bolt, tightening it to the correct torque specification per the service manual. Do not overtighten to prevent stripping threads.

Step 5 – Refill with Fresh Coolant

  • Remove the radiator cap completely.
  • Slowly pour in new coolant to fill the radiator. Allow air bubbles to escape and gently rock the bike side to side to purge trapped air from the system.
  • Many technicians recommend loosening the radiator bleed screw (if equipped) while filling to further reduce the risk of air locks in your FC450HQ's large dual-radiator setup.
  • Continue to fill until coolant reaches the top of the neck.
  • Reinstall and securely tighten the radiator cap.

Step 6 – Start and Bleed the System

  • Start the engine and let it idle for a few minutes with the radiator cap on. This circulates coolant and helps expel any remaining air from the system.
  • Shut off the engine and allow it to cool. Recheck the coolant level and top up if necessary.

Finishing Touches & Special Model Notes

  • Inspect around the water pump, hose connections, and radiators for leaks.
  • Reinstall the right side cover and any other removed parts.
  • The 2015 Husqvarna FC450HQ uses a high-performance cooling system designed for race-level heat management. Always use a coolant that meets or exceeds OEM specification, especially if riding in extreme temps or under high load.
  • Monitor your coolant level regularly, especially after the first ride post-change, as any trapped air may still escape during extended operation.

Routine cooling system maintenance is vital to keep your FC450HQ running cool and strong on the track or the trails. For all the parts, accessories, and genuine Husqvarna service items you need, MotoSport is your go-to destination for dirt bike essentials.

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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.