How to Change the Coolant in a 2020 Honda CRF450RWE

Shop parts for a 2020 Honda CRF450RWE Dirt Bike.

Changing the coolant in your 2020 Honda CRF450RWE is an essential maintenance step to preserve peak engine performance, optimal temperature control, and component longevity. Follow this MotoSport proprietary guide for a successful coolant replacement – and keep in mind any unique details about the CRF450RWE that you need to know as an owner.

Why Coolant Change Is Critical

  • High-performance engines like the CRF450RWE run hotter than most trail bikes, especially since this model is tuned for motocross, so old or contaminated coolant can lead to overheating issues, power loss, and mechanical damage.
  • Honda recommends checking for radiator leaks, dirty fins, and cracked hoses, as failure points are more common on competition-spec machines due to the stress of racing and aggressive riding.

Preparation

  • Work with a cold engine to avoid burns and ensure safe coolant handling.
  • Gather glycol-based motorcycle coolant (pre-mixed is preferred or dilute with distilled water only if concentrated), a new drain bolt washer, basic hand tools, and rags.

Step-by-Step Coolant Replacement

  1. Remove the radiator cap.
    With the bike off and completely cool, unscrew the radiator cap to release pressure and enable quick draining.
  2. Drain old coolant.
    Locate the water pump drain bolt – usually at the bottom of the pump cover. Place a tray underneath and remove the bolt to begin draining.
    Allow all fluid to drain thoroughly. For faster draining, remove the radiator cap first. The CRF450RWE typically holds just over 1 quart of coolant, so be ready for the volume.
  3. Inspect components.
    Check the drain bolt washer and replace if worn. Inspect hoses, fins, and overflow tube for cracks or blockages. Look for signs of leaks at the water pump check hole, as the CRF450RWE is prone to seal wear due to higher RPM use.
  4. Reinstall the drain bolt.
    Fit a new copper washer and torque the drain bolt to 10 N·m (7 lbf·ft).
  5. Refill with fresh coolant.
    Pour coolant into the radiator slowly up to the bottom of the filler neck. Gently rock the bike side to side to release air pockets. The correct capacity at coolant change for the CRF450RWE is 1.09 US qt (1.03 liter).
  6. Bleed air and top off.
    Start the engine and let it idle briefly with the cap off. Squeeze the radiator hose gently to help air escape. Turn off, let cool, and re-check the level. Continue topping until the fluid reaches the bottom of the filler neck.
  7. Secure the radiator cap.
    Install the radiator cap tightly. If not properly secured, coolant may leak out during operation – risking overheating or engine damage.
  8. Final system checks.
    Confirm all components are leak-free and hoses are properly routed. Ensure overflow tube is clear and connected.

CRF450RWE Model Notes

  • The CRF450RWE model features upgraded cooling designs, lightweight radiators and higher flow for race use, but is also more sensitive to debris or fin damage. Regular maintenance is needed for radiator fin cleaning and checking for leaks in tracks with heavy roost or mud.
  • Coolant expansion and overflow may be more noticeable due to aggressive engine mapping — always monitor the overflow tube and expansion bottle after hard rides.

Pro Tips for MotoSport Riders

  • Always use motorcycle-specific coolant; automotive coolants can damage seals and promote wear on high-revving motocross engines.
  • Flush the cooling system every 12–24 months, or after extensive racing or if overheating is noted.
  • For best results, clean the radiator exterior thoroughly at every coolant change.

Maintaining your 2020 Honda CRF450RWE’s cooling system is vital. If you need replacement parts – from radiators to hoses and cooling accessories – Shop parts for a 2020 Honda CRF450RWE Dirt Bike..

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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.