How to Change the Coolant in a 2015 Honda CRF150R Big Wheel
Shop parts for a 2015 Honda CRF150R Big Wheel Dirt Bike.
Keeping your 2015 Honda CRF150R Big Wheel running at peak performance requires regular maintenance, and changing the coolant is one critical task every owner should handle. The CRF150R Big Wheel, also known as the CRF150RB, is a high-revving, competition-designed dirt bike that experiences significant engine heat under hard riding conditions. Over time, coolant degrades and loses its effectiveness, which can lead to overheating – especially critical for a four-stroke race bike like the CRF150RB.
What You Need
- Fresh, high-quality coolant (Honda recommends Pro Honda HP Coolant)
- 12mm socket wrench
- Drain pan
- Funnel
- Clean rags or shop towels
- Distilled water (if flushing)
- Gloves & safety glasses
Steps to Change the Coolant
- Ensure the Bike is Cool: Allow the engine to cool completely before servicing. Opening the radiator cap on a hot engine can result in burns from hot coolant or steam.
- Remove the Radiator Shroud: Take off the left-side radiator shroud for easier access to the radiator cap.
- Place Drain Pan: Position a drain pan under the water pump area on the right side of the engine.
- Remove Water Pump Drain Bolt: Locate the water pump at the lower right side of the engine. Using a 12mm socket, remove the bolt (often has a copper washer) at the bottom of the water pump housing. This will begin draining the coolant (this bolt is specific to the 2015 CRF150RB and should always be carefully reinstalled to avoid leaks).
- Open the Radiator Cap: Slowly open the radiator cap to allow air in and help coolant drain faster.
- Flush if Needed: If the old coolant is dirty or you've never changed it, pour distilled water into the radiator to flush the system. Reinstall the drain bolt, fill with distilled water, run the engine briefly (30-60 seconds, watching the temperature), then drain again. Repeat until the water runs clear.
- Reinstall the Drain Bolt: Replace the drain bolt using a new copper washer if necessary, and torque to manufacturer specification to avoid leaks (do not overtighten, as aluminum threads can strip easily).
- Fill with New Coolant: Using a funnel, pour fresh coolant into the radiator until it reaches the neck. This model requires approximately 0.8 US quarts (0.76 L) after a full drain (double-check your level after burping the system).
- Burp the Cooling System: Slowly rock the bike side to side and give the upper hose a gentle squeeze to release any trapped air. Add more coolant if needed.
- Replace Radiator Cap and Shroud: Securely reinstall the radiator cap and the side shroud.
- Start and Check: Start the bike and let it warm up fully. Once the thermostat has opened, let it cool and recheck the coolant level, topping off if necessary. Inspect the drain bolt and hose connections for leaks.
Things to Know About the CRF150R Big Wheel (CRF150RB)
- Racing Focused: The CRF150RB is designed for competition – the higher compression and high-revving engine makes cooling efficiency especially important during extended, hard riding.
- Cooling System: This model has a relatively small coolant capacity, so even a small drop in level or a minor leak can quickly lead to overheating and engine damage.
- Coolant Selection: Always use a recommended premix motorcycle coolant designed for aluminum engines – automotive or diluted universal coolant can degrade seals or cause corrosion.
- Regular Checks: Inspect the radiator and hoses for mud, debris, or pinhole leaks after every few rides, as race bikes are exposed to far more grit and vibration than trail models.
- Overheat Protection: The radiator cap on the CRF150RB has a specific pressure rating; using a cap with a different rating can compromise cooling efficiency and risk blowing seals.
Disposal
Never pour old coolant down the drain or onto the ground. Collect it in a suitable container and take it to your local recycling center or hazardous waste facility.
Quick Maintenance Recap
- Replace coolant at least once a year or any time it looks cloudy, rusty, or contaminated.
- Use only the correct type of coolant for aluminum engines.
- Always check the coolant level before race days or after any big ride.
Related Shopping Categories
Shop Radiators for a 2015 Honda CRF150R Big Wheel Dirt Bike.
Shop Coolant for a 2015 Honda CRF150R Big Wheel Dirt Bike.
Shop Temperature Sensors for a 2015 Honda CRF150R Big Wheel Dirt Bike.
Shop Tools for a 2015 Honda CRF150R Big Wheel Dirt Bike.
Shop Radiator Hoses for a 2015 Honda CRF150R Big Wheel 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.