How to Change the Coolant in a 2024 KAWASAKI KLX300SM

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Regularly changing the coolant in your 2024 Kawasaki KLX300SM is essential for optimal performance – especially if you ride in challenging or variable environments. Coolant maintains the bike’s safe operating temperature, prevents corrosion, and maximizes engine life. The KLX300SM is a supermoto designed for both urban and light off-road use, meaning it’s exposed to wide temperature swings and extended high-RPM runs, which makes coolant quality particularly important.

Tools & Supplies You Will Need

  • 10mm socket and ratchet
  • 8mm socket (for side panel removal)
  • Phillips head screwdriver (for bleeder screw, if equipped)
  • Catch pan for used coolant
  • Coolant compatible with aluminum motorcycle radiators (silicate-free, premixed recommended)
  • Funnel
  • Bottled or distilled water (for flushing, optional)
  • Clean rags
  • Gloves and safety glasses

Step-By-Step Coolant Change Process

  1. Preparation:
    Allow the engine to cool completely before you begin to avoid burns. Place the bike on a stable stand or the side stand on level ground.
  2. Remove the Side Panel:
    Use the 8mm socket to remove the left side panel. This exposes the coolant reservoir for easier access.
  3. Drain the Old Coolant:
    With a catch pan in place, remove the radiator cap slowly to relieve pressure.
    Locate the coolant drain bolt – typically on the water pump (lower right side of the engine). Use a 10mm socket to unscrew the drain bolt and let the coolant fully drain. Remove the reservoir cap and tip out any leftover coolant in the tank. If your bike has a radiator bleeder screw, open it with a Phillips screwdriver to ensure complete drainage and airflow.
  4. Flush the System (Optional but Recommended):
    If you want a thorough clean, briefly reinstall the drain bolt and fill the system with distilled water. Start the bike for a minute (do not let it heat up). Shut down, allow to cool, and drain again. Repeat until the water runs clear.
  5. Refill with New Coolant:
    Replace and tighten the drain bolt (do not overtighten). Begin adding fresh coolant through the radiator filler neck using a funnel. Pour slowly to avoid air bubbles. Fill to the base of the filler neck. Fill the coolant reservoir to the indicated level as shown on the tank.
    If equipped, close the bleeder screw once coolant runs bubble-free. Reinstall the radiator cap, making sure it’s firmly seated.
  6. Check for Leaks & Air:
    Start the engine and let it idle for several minutes. Occasionally rev the engine gently to help circulate coolant and release any trapped air. Monitor for fluid leaks and recheck the reservoir, topping it off as needed after the first test ride.
  7. Reinstall the Side Panel:
    Secure the side panel with the 8mm bolts.
  8. Proper Disposal:
    Used coolant is toxic. Take it to a hazardous waste collection center – never pour it down the drain or onto the ground.

KLX300SM Model-Specific Notes

  • The 2024 KLX300SM radiator is positioned for maximum airflow, so check for bugs or debris in the fins after your service.
  • This model’s liquid cooling system operates under higher temperatures than trail bikes – always verify coolant compatibility with aluminum radiators.
  • Supermoto setups may be exposed to urban idling and abrupt acceleration, increasing the risk of overheating – regular coolant inspection helps avoid unexpected issues.
  • Never substitute traditional automotive coolants with silicates or older formulas as they can damage the water pump and corrode the system.

When Should You Change the Coolant?

  • Every 2 years or 12,000 miles (whichever comes first), or sooner if the coolant looks dirty, rusty, or you have overheated the engine.
  • After deep stream crossings or hard off-road use, inspect the overflow tank for water contamination.

Keeping your KLX300SM’s cooling system maintained ensures smooth riding, better performance & long engine life.

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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.