How to Change the Coolant in a 2019 Honda CRF450L

Shop parts for a 2019 Honda CRF450L Dirt Bike.

Changing the coolant in your 2019 Honda CRF450L ensures the bike's liquid-cooled engine runs at optimal temperature and maximizes performance on the trail. This guide outlines the exact steps, essential precautions, and notes specific to the CRF450L.

Why Coolant Maintenance Matters for CRF450L Owners

The 2019 CRF450L features a high-output, fuel-injected, liquid-cooled Unicam engine, meaning efficient heat dissipation is vital for longevity and performance through aggressive off-road use. Honda recommends changing coolant every two years or after significant hours of use to prevent overheating, scale buildup, and corrosion in the cooling system.

What You Need

  • 50/50 premixed, silicate-free coolant for aluminum engines
  • 5mm Allen key
  • 8mm – 10mm sockets
  • Ratchet
  • Phillips screwdriver
  • Paper towels
  • Drain pan
  • New crush washer for drain bolt (recommended)

Step-by-Step Coolant Change Guide

  1. Preparation
    • Ensure the motorcycle is completely cold before you begin.
    • Position it upright on a stand to keep the coolant level balanced and prevent spillage.
  2. Remove Skid Plate and Panels
    • Use the 5mm Allen key to remove the bolts securing the engine skid plate. This gives access to the water pump drain bolt at the lowest section of the pump housing.
    • If equipped, remove the right-side radiator shroud using the 8mm socket and Phillips screwdriver as needed.
  3. Open the Radiator Cap
    • Use a Phillips screwdriver to remove the safety screw holding the radiator cap.
    • Unscrew the cap to vent the system, allowing coolant to drain smoothly.
  4. Drain the Coolant
    • Locate the water pump drain bolt at the bottom of the pump housing. Loosen and remove using a 10mm socket. The crush washer may be stuck to the bolt—replace with a new washer if possible.
    • Let all coolant drain into the pan until the flow stops.
  5. Flush the Radiator (Optional but Recommended)
    • If the old coolant was dirty, pour distilled water into the radiator, replace the cap, and run the bike for a minute. Repeat drain and refill to ensure optimal cleanliness before adding new coolant.
  6. Reinstall Drain Bolt
    • Fit the new crush washer on the bolt. Torque the drain bolt to Honda spec – 18 ft-lbs – to prevent leaks but avoid overtightening.
  7. Refill Coolant
    • Slowly pour new silicate-free coolant into the radiator until the level reaches just beneath the filler neck.
    • If equipped, fill the expansion reservoir to the indicated line.
  8. Bleed Air from System
    • Reinstall the radiator cap and panels. Start the bike and let it idle for three minutes, cycling the coolant through the engine. Shut off and let it cool fully—then remove the cap and top off as needed.
  9. Final Checks
    • Inspect for leaks at the drain bolt and around hoses. Tighten or adjust if necessary.
    • Recheck coolant levels after the first ride and top off the reservoir if needed.

Model-Specific Tips for the CRF450L

  • The CRF450L uses a lightweight radiator with tight clearances—avoid overfilling and over-tightening any bolts.
  • Always use a crush washer for the drain bolt. This model is known for slow leaks when reused.
  • If you install aftermarket radiator guards or skid plates, you may need extra steps or different size tools for removal/reinstallation.

When to Change Coolant

  • Every two years
  • Anytime you see rust, scale, or mud in drained coolant
  • After deep water crossings or long storage periods

Safety Precautions

  • Always change coolant when the engine is cold to prevent burns from steam or pressurized fluid.
  • Dispose of old coolant at a recycling center—never pour it on the ground.

Take pride in maintaining your CRF450L—proper cooling is key to reliable, high-performance rides for years to come.

Related Shopping Categories

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Shop Radiator Hoses for a 2019 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.