How to Change the Coolant in a 2019 Honda CRF250RX

Shop parts for a 2019 Honda CRF250RX Dirt Bike.

Routine coolant changes keep your 2019 Honda CRF250RX running cool, especially under the demands of competitive off-road riding. Proper cooling is critical for optimum engine performance and longevity, so following the right steps is vital for every owner.

Tools and Materials Needed

  • Silicate-free motorcycle coolant (approx. 0.98 US qt for change)
  • Basic metric socket set (including 8mm and 10mm sockets)
  • 5mm Allen key
  • Phillips screwdriver
  • Drain pan
  • Funnel
  • New crush washer for drain bolt
  • Paper towels or rags
  • Distilled water (for flushing, if desired)

Model-Specific Notes

  • The CRF250RX is based on Honda's MX platform, adapted for GNCC, enduro, and trail riders, with a cooling system optimized for technical and sustained low-speed riding.
  • On this model, never open the radiator cap when the engine is hot – pressure can cause hot coolant to spray, risking serious burns.
  • Be mindful of the plastics: Remove only what's necessary for access to the radiator cap and coolant drain bolt.
  • Expect normal losses of 0.7 – 2.0 US oz (20 – 60 cm3) through the overflow; higher losses could signal a cooling system problem.

Step-by-Step Coolant Change Procedure

  1. Preparation:
    • Ensure the engine is cool — let the bike sit at least an hour after running.
    • Place the bike upright and stable on a stand.
  2. Remove Shrouds (if needed):
    • Use your 5mm Allen key and sockets to remove the radiator shroud bolts on both sides to access the radiator cap and filler neck.
  3. Open the Cooling System:
    • Slowly unscrew the radiator cap; press down lightly to release pressure in stages.
  4. Drain Old Coolant:
    • Position a drain pan below the water pump cover. Locate the coolant drain bolt on the right side of the engine (usually 8mm – confirm for your bike).
    • Remove the bolt and washer, allowing coolant to drain completely from both the radiator and engine. Opening the cap earlier helps drainage.
  5. Flush (Optional but Recommended):
    • Pour distilled water into the radiator to flush any debris, letting it run out the open drain. Repeat until the water runs clear.
    • If switching coolant types (such as to Engine Ice or similar), flush once more with a 50/50 mix of vinegar and water, then flush thoroughly with distilled water to remove residue.
  6. Replace Drain Bolt:
    • Install a new crush washer onto the drain bolt and torque to spec (do not overtighten – 7 to 9 lb·ft is typical; check your manual).
  7. Refill with Coolant:
    • Using a funnel, pour fresh silicate-free coolant into the radiator until the level is just below the filler neck.
    • Do NOT reinstall the radiator cap yet.
  8. Remove Trapped Air:
    • Gently rock the bike side to side about 20° each way several times to dislodge air bubbles. Add coolant if the level drops.
    • Repeat until the level remains steady.
  9. Reinstall Radiator Cap:
    • Once satisfied the system is full and air-free, securely reinstall the cap.
  10. Bleed the System:
    • Start the engine and idle for 2–3 minutes with the bike level. Do not rev at high RPM while cold.
    • Blip the throttle a few times – this helps purge lingering air.
    • Shut down the engine, let it cool, remove the cap, and top off as needed.
  11. Check for Leaks and Finalize:
    • Inspect the drain bolt area and hoses for leaks.
    • Reinstall shrouds and any removed panels.
    • Check the coolant level in the expansion tank and bring to between MIN and MAX marks. Reinstall the tank cap.

Pro Tips & Ownership Reminders

  • Honda recommends coolant changes every two years or after extreme use.
  • Use only premixed or distilled water-mixed coolant designed for aluminum radiators – tap water and automotive coolants can cause corrosion.
  • If you ride in muddy or ultra-dusty conditions, inspect the radiator fins and clean as needed. Overheating is common when debris limits airflow.
  • Monitor your coolant reservoir between rides – unusual drops can point to head gasket or radiator cap issues.

Keeping your 2019 CRF250RX's cooling system maintained helps guarantee consistent performance, whether you're racing GNCC or exploring the trails. Never skip this simple, crucial service.

Related Shopping Categories

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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.