How to Change the Coolant in Your 2018 Honda CRF250R: MotoSport.com Exclusive Guide

Shop parts for a 2018 Honda CRF250R Dirt Bike.

Routine maintenance is key to keeping your 2018 Honda CRF250R running at peak performance. Changing the coolant is especially critical for race-spec engines like the CRF250R, which operate at high temperatures and RPMs. Follow this proprietary MotoSport guide for a safe, thorough coolant change that matches the engineering specs of Honda's award-winning motocross machine.

What Makes Coolant Service Critical for the 2018 CRF250R?

  • High-revving, lightweight engine – The CRF250R's liquid-cooled DOHC four-stroke runs hot under race conditions, making optimal coolant protection essential.
  • Aluminum components – Use only a 50/50 silicate-free coolant mix to prevent corrosion & scale in the alloy radiator and engine parts.
  • Honda-specific maintenance intervals – Change the coolant every 2 years or at 24,000 miles (whichever comes first) for best results.

Tools and Supplies Needed

  • Silicate-free antifreeze/coolant (Honda GN4 or equivalent)
  • Funnel
  • Drain pan
  • 5mm Allen key
  • 8mm & 10mm sockets, ratchet
  • Phillips screwdriver
  • Single-use crush washer (for radiator drain bolt)
  • Clean shop towels

Step-by-Step Coolant Change Guide

  1. Preparation
    Allow the engine & radiator to cool completely before starting. Hot coolant can spray out – risking serious burns. Place your bike on a stand and remove side shrouds and plastics as needed for clear access to the radiator.
  2. Drain the Old Coolant
    Using the correct socket, carefully remove the radiator drain plug and allow all coolant to flow into a pan. Replace the crush washer on the drain bolt.
  3. Flush (Optional but Recommended)
    For best results, pour distilled water into the radiator, temporarily reinstall the cap, run the engine briefly, and then drain again to clear residues. Repeat until drainage runs clear.
  4. Refill with New Coolant
    Open the radiator cap. Slowly pour silicate-free 50/50 coolant mix into the filler neck until level reaches the bottom of the neck (Capacity: approx. 0.98 US qt at change). Do not overfill – if expanded coolant exits via overflow, that's normal up to 2 US oz per ride.
  5. Bleed the Cooling System
    With cap installed, lean the CRF250R about 20° to each side to help trapped air escape. Start the engine, let it idle with the radiator cap on, then cool down and carefully re-check the coolant level. Top off if needed before your next ride.
  6. Final Inspection
    Reinstall all body panels in reverse order, torque bolts to Honda specs, and inspect for leaks. Confirm the radiator cap is fully locked – listen for two clicks.

Special Model Notes for 2018 CRF250R Owners

  • This model features a compact twin-spar aluminum frame – avoid aggressive coolant flush agents that might etch or corrode aluminum.
  • Latest model lithium-ion battery is close to the radiator – disconnect negative battery cable only if your process risks fluid contact.
  • Keep an eye on overflow tube loss: more than 2 US oz per ride means a system check is needed.

Quick Tips for Reliable Cooling Performance

  • Always use Honda-approved coolant designed for dirt bike applications.
  • Replace the drain plug crush washer every coolant service for proper sealing & protection.
  • If installing aftermarket radiators or hoses, ensure compatibility with factory fitment and materials.
  • Check coolant level before each ride – overheating can cause rapid engine damage.

With MotoSport's exclusive CRF250R guide and parts support, your bike will stay cool – so you can ride hard every time.

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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.