How to Change the Coolant in a 2009 Honda CRF150R

Shop parts for a 2009 Honda CRF150R Dirt Bike.

Regular coolant changes are vital to keeping your 2009 Honda CRF150R running cool, especially under the stress of motocross riding. The CRF150R—Honda's championship-winning mini-race bike—uses a high-revving four-stroke that generates significant heat, making a properly maintained cooling system essential for engine longevity and peak performance. Follow this MotoSport-exclusive guide for a thorough, model-specific coolant change.

What You'll Need

  • OEM-recommended coolant or high-quality glycol-based motorcycle coolant (do not mix types)
  • Distilled water (for flushing)
  • 8mm socket or wrench
  • New copper drain washer (recommended)
  • Drain pan
  • Funnel
  • Protective gloves and eyewear

Steps to Change the Coolant

  • Let the bike cool completely. The CRF150R runs hot, and opening the system while hot can cause serious burns. Only change coolant at room temperature.
  • Remove the radiator cap. This is essential to relieve system pressure and allow coolant to drain freely.
  • Locate the coolant drain bolt. On the CRF150R, it's the lowest bolt on the water pump cover. Position your drain pan below this bolt.
  • Loosen and remove the drain bolt. Allow all old coolant to flow out. Inspect and, if necessary, replace the copper washer to prevent leaks.
  • Flush the system (recommended). Temporarily reinstall the drain bolt and fill the radiator with distilled water. Remove the bolt and let the water drain to flush out residue. Repeat until only clear water exits.
  • Reinstall and torque the drain bolt. Tighten it to 10 Nm (88 in-lb) to avoid damaging the threads or causing leaks.
  • Fill with new coolant. Slowly pour coolant into the radiator until you reach the neck. Allow time for air to escape. The CRF150R has narrow passageways, so patience prevents trapped air and potential overheating.
  • Bleed the cooling system. Gently rock the bike from side to side, then kick the engine over by hand several times (with the kill switch off) to circulate coolant and release air bubbles. Top off as needed.
  • Reinstall the radiator cap. Ensure it clicks securely into place.
  • Check for leaks. Start the engine and let it idle until fully warm. Watch the coolant level in the radiator (remove the cap after the bike has cooled if necessary) and top off after your first ride, as level may drop while air escapes from the system.

CRF150R-Specific Notes

  • The CRF150R uses a two-radiator system for superior cooling–ensure both are filled evenly.
  • If the bike has experienced overheating, inspect for blown head gaskets or warped components, as overheating can be more common in race bikes like the CRF150R.
  • Never use automotive coolant with silicates or phosphate, which can damage motorcycle water pumps and radiators.
  • Coolant should be replaced every season or more frequently during high-performance riding.
  • Aftermarket oversized radiators are a popular upgrade for hard-charging CRF150R riders–if equipped, verify any additional bleed ports during filling.

Proper coolant maintenance helps ensure your 2009 CRF150R delivers crisp throttle response and stays reliable throughout your season. Keep it factory cool and ride on.

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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.