How to Change the Coolant in a 2018 KTM 350SXF

Shop parts for a 2018 KTM 350SXF Dirt Bike.

Regular coolant changes are essential for maintaining peak performance & longevity of your 2018 KTM 350SXF. This guide offers a step-by-step walk-through tailored specifically for your dirt bike, plus key considerations for KTM owners.

What You Will Need

  • Fresh coolant compatible with KTM motors (ready-to-use, non-silicate antifreeze recommended by KTM)
  • 8 mm socket or wrench
  • Drain pan or container
  • Funnel
  • Rags for cleanup
  • Optional: Compressed air

Preparation

  • Ensure the engine is completely cool to prevent burns.
  • Place your 350SXF on a secure stand for stability.
  • Remove the seat & side fairings if they block access to the radiator cap.

Drain the Old Coolant

  • Remove the radiator cap slowly to relieve any residual pressure.
  • Locate the coolant drain bolt on the water pump (right side of engine).
  • Place the drain pan underneath and unscrew the drain bolt using your 8 mm wrench.
  • Let the coolant fully drain into your pan. To ensure a complete drain, gently tip the bike from side to side.
  • If you want a thorough flush, refill the cooling system with distilled water, reinstall the bolt, start the engine briefly, then drain again.

Flush (Optional but Recommended)

  • If you’re switching coolant types or have sediment, flushing removes contaminants from the system.
  • After draining the main coolant, refill with distilled water, run the engine a short time, then repeat the drain process.

Refill with New Coolant

  • Reinstall & tighten the coolant drain bolt securely (do not over-torque).
  • Pour in the new coolant using a funnel until the radiator is full.
  • On the KTM 350SXF, elevating the front wheel 18 to 19 inches can help purge trapped air for a complete fill.
  • Loosen the cylinder bleed screw (if applicable) and fill coolant until you see fluid at the bleed; tighten screw.
  • Install the radiator cap securely.

Bleed the System & Final Steps

  • Start the bike and let it idle with the radiator cap on. Briefly rev the engine a few times to move air bubbles to the top.
  • Shut off the engine and let it cool.
  • Remove the cap once more and top off coolant if necessary.
  • Check for leaks at the drain bolt and hoses before riding.

Special Notes for the 2018 KTM 350SXF

  • The KTM 350SXF runs relatively high temperatures under aggressive riding. Always monitor for signs of overheating — steam, coolant loss, or the fan regularly engaging can indicate issues.
  • This model’s cooling system is shared with other KTM/Husqvarna 350s, and the process is consistent across similar years.
  • Aftermarket radiators or oversized radiators require the same process but may affect coolant volume — ensure you check manual capacity for your particular setup.
  • Only use coolants approved for aluminum components to prevent corrosion specific to KTM’s radiators and water pumps.

Dispose of Used Coolant Responsibly

  • Never pour old coolant down the drain or onto the ground. Take it to a proper hazardous waste facility or automotive recycling center.

Changing the coolant on your KTM 350SXF is straightforward if you follow the right procedure and pay attention to model-specific care. For performance parts, OEM replacements, or specialty coolants, shop MotoSport.com for a 2018 KTM 350SXF Dirt Bike..

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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.