How to Change the Coolant in a 2020 Honda CRF450L

Shop parts for a 2020 Honda CRF450L Dirt Bike.

Regular coolant changes are critical for maintaining the performance and longevity of your 2020 Honda CRF450L, especially under demanding off-road conditions. Here is a MotoSport-exclusive, step-by-step guide tailored specifically for your CRF450L, including model-specific insights and best practices for a hassle-free DIY experience.

What You Will Need

  • Silicate-free motorcycle coolant (check for CRF450L compatibility)
  • Ratcheting wrench – 8mm and 10mm sockets
  • 5mm Allen key
  • Phillips screwdriver
  • Drip pan & damping rags
  • New crush washer for the water pump/coolant drain bolt
  • Funnel
  • Protective gloves & goggles

Preparation

  • Ensure the engine is completely cool before starting. The 2020 CRF450L's cooling system operates under pressure and hot coolant can cause serious burns.
  • Position the bike upright on a stable stand for easy access.

Step 1 – Remove Panels & Skid Plate

  • Remove necessary plastic panels around the radiator with a 5mm Allen key. On the right side, you'll typically remove four screws and two plastic retainers for better access.
  • If your CRF450L has a skid plate, remove it using the assigned socket or Allen key (generally 8mm or 10mm bolts). Removing the skid plate grants clear access to the water pump and the coolant drain bolt beneath it.

Step 2 – Drain the Old Coolant

  • Locate the coolant drain bolt at the bottom of the water pump. Place the drip pan underneath to catch old coolant.
  • Slowly loosen and remove the drain bolt along with its crush washer. Allow coolant to fully drain. Open the radiator cap (secured by a Phillips screw) for faster draining.
  • Inspect and replace the crush washer to prevent future leaks.

Step 3 – Reinstall Drain Bolt

  • Once all coolant has completely drained, reattach the drain bolt using a new crush washer. Torque it to Honda's spec (typically around 18 ft-lb or as outlined in your model's service manual) to ensure a proper seal.

Step 4 – Refill the Radiator

  • Insert the funnel into the radiator opening and slowly pour in fresh, silicate-free coolant until it reaches the top of the neck.
  • Fill the coolant reservoir (if equipped on your CRF450L) to the max line.

Step 5 – Bleed Air from the Cooling System

  • With the radiator cap off, start the engine and let it idle for a few minutes. Watch for air bubbles escaping from the radiator neck as trapped air purges out.
  • When bubbles stop and the coolant drops slightly, top off the radiator. Do not allow the engine to overheat or run for extended periods in this state.
  • Install the radiator cap securely once purging is complete.

Step 6 – Check for Leaks & Reinstall Panels

  • Examine the drain bolt and cooling system connections for leaks before reinstalling the skid plate and bodywork. Tighten all removed fasteners to spec.
  • Wipe up any spilled coolant to prevent damage to components or paint.

Step 7 – Final Checks

  • Start the motorcycle and warm it up fully. After cooling, re-check coolant levels in both radiator and reservoir. Top off if necessary. Verify there are no leaks during and after operation.

Model-Specific Notes for the 2020 Honda CRF450L

  • The factory system uses a pressurized radiator cap – always open slowly and only when the engine is cold.
  • Pay close attention to the orientation and seating of the radiator cap and reservoir lines, as the CRF450L's high-compression engine generates considerable heat under load.
  • Inspect hoses for swelling or deterioration, especially if you ride in extreme conditions or have high engine hours – consider upgrading to reinforced hoses for improved durability.
  • Failure to use the proper silicate-free coolant may cause water pump seal damage or reduced corrosion resistance, both of which compromise performance.

If you ride hard or under extreme weather conditions, check coolant levels more frequently and consider changing coolant annually instead of the manufacturer's extended interval.

Stay on top of your CRF450L's performance – coolant changes are one of the simplest and most effective maintenance routines for reliable power, consistent cooling, and long engine life. If you need OEM or aftermarket parts, shop parts for a 2020 Honda CRF450L Dirt Bike.

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Shop Radiator Hoses for a 2020 Honda CRF450L Dirt Bike.

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.