How to Change the Coolant in a 2019 Honda CRF450RX
Shop parts for a 2019 Honda CRF450RX Dirt Bike.
Regular coolant changes are critical to the performance and longevity of your 2019 Honda CRF450RX. The CRF450RX features a high-performance liquid-cooled engine built for off-road racing – overheating or using degraded coolant risks engine damage and diminished power. Follow this MotoSport guide for a quick, clean, and safe coolant swap tailored for the MMY CRF450RX.
What You Need
- Silicate-free, pre-mixed coolant
- Replacement crush washer for drain bolt
- 5mm Allen key
- 8mm and 10mm socket – ratchet
- Phillips screwdriver
- Funnel
- Paper towels/shop rags
- Torque wrench
Step-by-Step Coolant Change
- Let the bike cool completely. Never open the radiator cap on a hot engine—scalding coolant and vapor can cause serious burns.
- Remove the engine guard: Use your 8mm or 10mm socket to take off the engine guard bolts and guard. Hook the tabs on the guard to the frame as shown in your owner's manual when reinstalling. Properly route the radiator overflow hose for reassembly .
- Access the radiator:
- Remove the left-side plastic and set aside.
- Loosen or remove the bolts securing the coolant reservoir if present.
- Use the Phillips screwdriver to remove the radiator cap set screw, then take off the cap.
- Locate the drain bolt (usually at the bottom of the water pump housing):
- Place a drain pan underneath.
- Loosen the drain bolt with your socket. Remove and allow coolant to fully drain.
- Inspect and replace the crush washer on the drain bolt.
- Flush System (optional but recommended for race bikes):
- Pour a small amount of distilled water into the radiator and allow to drain.
- Reinstall Drain Bolt:
- Torque to Honda spec – 18 ft-lb (24 N·m) for the CRF series, and ensure the washer seats correctly to prevent leaks .
- Fill With New Coolant:
- Pour silicate-free coolant into the radiator until near the top.
- Replace and secure the radiator cap.
- Reinstall the set screw and reservoir.
- Prime the System:
- Start the engine (in a well-ventilated area) and let it idle for several minutes. This removes trapped air and circulates new coolant.
- Stop the engine, let it cool, and recheck the radiator level. Top off as needed.
- Check for Leaks and Final Steps:
- Inspect for leaks at the drain bolt and hose clamps.
- Reinstall plastics, engine guard, and secure all fasteners to Honda torque spec .
Special Notes for CRF450RX Owners
- The 2019 CRF450RX uses an advanced cooling system; always use silicate-free coolant to protect the magnesium and aluminum components.
- The coolant change interval recommended by Honda is every two yearsor sooner for racing and extreme conditions.
- Pay attention to proper hose routing and overflow hose placement when reassembling after service.
- After a coolant change, monitor coolant levels for the first few rides; any rapid drop may suggest an air pocket or leak.
Riding Ready
With your coolant freshly changed and your CRF450RX buttoned up, you're ready to hit the trails knowing your engine will stay protected and perform at its best. For replacement parts, Honda OEM items, or upgrades, Shop parts for a 2019 Honda CRF450RX Dirt Bike. and keep your 2019 Honda CRF450RX running strong.
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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.