How to Change the Coolant in a 2018 Kawasaki KLX140G

Shop parts for a 2018 Kawasaki KLX140G Dirt Bike.

Maintaining the cooling system on your 2018 Kawasaki KLX140G is essential for consistent performance and long engine life. Coolant prevents overheating, fights corrosion, and protects your engine through all riding seasons. Follow this detailed, MotoSport-exclusive guide to properly change the coolant on your KLX140G, ensuring peak performance on every ride.

Tools & Materials You Will Need

  • 10 mm socket and ratchet
  • Drain pan
  • Phillips screwdriver
  • Funnel
  • Fresh coolant (Kawasaki recommended or equivalent)
  • Distilled water (for flushing, optional)
  • Clean shop rags
  • Protective gloves & eyewear

KLX140G Model-Specific Note

The KLX140G is known for its compact, air-cooled engine and robust off-road reliability, but the radiator and hose locations can be more compact compared to full-size motocross bikes. Access to the radiator cap and drain bolt is straightforward due to minimal bodywork–making coolant changes simpler than on more tightly-packed models. Always ensure the engine is completely cool before starting, as the KLX140G's compact engine compartment can retain heat longer.

Preparation Steps

  • Ensure the motorcycle is on a level surface and the engine is completely cool.
  • Remove the right side panel if needed for easier access to the radiator cap and reservoir.
  • Place your drain pan beneath the engine and have shop rags ready for any spills.

Drain the Old Coolant

  • Remove the radiator cap by turning it counterclockwise to release any pressure in the cooling system.
  • Locate the coolant drain bolt at the base of the water pump on the right side of the engine (typically a 10 mm bolt).
  • Use the socket and ratchet to remove the drain bolt completely. Allow the coolant to drain fully into the pan.
  • To speed up draining and ensure a complete flush, gently tilt the bike side to side.
  • If the bike is equipped with a radiator bleeder screw (some models), loosen it to help air and coolant escape.

Flush the System (Recommended)

  • Reinstall the drain bolt and tighten securely.
  • Fill the radiator with distilled water. Replace the radiator cap and start the engine. Run for 1-2 minutes to circulate the water, then shut off the engine and allow it to cool.
  • Repeat the drain process to remove the flush water. Repeat this procedure if the water is still discolored.

Add New Coolant

  • Ensure the drain bolt is reinstalled and tightened to manufacturer specs.
  • Using a funnel, pour fresh coolant into the radiator until it reaches the filler neck.
  • If your KLX140G has a coolant overflow reservoir, fill it to the correct level as marked.
  • Reinstall the radiator cap securely.

Remove Air and Check Levels

  • Start the engine and let it run for several minutes, periodically revving slightly to help purge air bubbles.
  • Turn off the engine and let it cool fully. Check the coolant level at the radiator cap and reservoir; top off as needed.
  • Inspect for leaks at the radiator, hoses, and drain bolt.

Final Checks

  • Reinstall any side panels you removed during the process.
  • Dispose of old coolant properly–never pour it down a drain or onto the ground.

Model-Specific Tips for the 2018 KLX140G

  • The KLX140G uses a simple, non-pressurized overflow system with easy-to-access components, ideal for DIY maintenance.
  • Double-check hose clamps for tightness after a ride or two post-coolant change–off-road vibrations can loosen fittings.
  • If riding in extreme conditions, consider a high-performance coolant compatible with aluminum engines.

Changing the coolant in your KLX140G keeps your off-road machine at its best, ready for every trail, track, or weekend adventure. For OEM and performance parts, MotoSport keeps your ride prepped–from gaskets to coolants, we have everything you need.

Related Shopping Categories

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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.