How to Change the Coolant in a 2018 Honda CRF250L

Shop parts for a 2018 Honda CRF250L Dirt Bike.

Keeping the cooling system of your 2018 Honda CRF250L in top condition ensures reliable performance on every ride. Routine coolant changes every two years or 24,000 miles–whichever comes first–are recommended for this dual sport machine. Follow this step-by-step MotoSport-exclusive guide to ensure you tackle the job confidently and safely.

Tools & Supplies Needed

  • Silicate-free motorcycle coolant with corrosion inhibitors
  • 10mm socket and ratchet
  • 8mm socket
  • 5mm Allen key
  • Phillips head screwdriver
  • Funnel
  • Paper towels or rags
  • Replacement crush washer (for drain bolt)

Before You Begin

  • Work on a cool engine to avoid burns from hot coolant.
  • Position the motorcycle upright on a firm, level surface with the ignition OFF.

Step 1: Remove the Plastics

  • Remove the top 5mm Allen screw holding the left side radiator shroud.
  • On the right side, remove four screws and two plastic retainers to access the reservoir and radiator area.
    Keep hardware organized for reassembly.

Step 2: Access the Radiator & Reservoir

  • Use a 10mm socket to remove the two bolts securing the coolant reservoir bottle.
  • Remove the Phillips screw from the radiator cap guard.
  • Take off the radiator cap slowly to relieve any pressure.

Step 3: Drain the Old Coolant

  • Locate the drain bolt at the bottom of the water pump (right side, engine lower area).
  • Place a catch pan beneath. With an 8mm socket, loosen the drain bolt and allow coolant to flow out completely.
  • Remove the reservoir cap and drain it as well.
  • Replace the single-use crush washer on the drain bolt to prevent leaks before reinstalling and tightening the bolt securely.

Step 4: Add the New Coolant

  • Using a funnel, slowly pour fresh coolant into the radiator until full.
  • Fill the reservoir to the specified "MAX" line.
  • Install the radiator cap and secure the reservoir in place.

Step 5: Bleed Air from the System

  • Start the engine and let it idle for a few minutes with the radiator cap on.
  • Shut off the engine and allow it to cool. Remove the radiator cap and check for air bubbles.
  • Top off coolant as needed. Repeat until the level remains stable with no visible bubbles or drops.

Step 6: Reinstall the Plastics

  • Replace the side shrouds and secure all fasteners to their original torque.

Step 7: Final Checks

  • Inspect for leaks at the drain bolt and around the radiator.
  • Ensure the coolant reservoir is filled to the mark.

Notes for CRF250L Owners

  • The CRF250L uses an aluminum engine and cooling components. Only use silicate-free coolant formulated for aluminum engines to prevent damage.
  • If equipped with an aftermarket skid plate, additional fasteners may need removal for access.
  • Never open the radiator cap while the engine is hot.
  • Always properly dispose of used coolant—it is toxic and harmful to the environment.

Staying proactive about cooling system maintenance helps protect your Honda CRF250L engine over countless miles, whether on city streets or backcountry trails. Regular coolant changes and careful attention to detail will keep your ride cool, adventure-ready, and dependable.

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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.