How to Change the Coolant on a 2019 Kawasaki KX450
Shop parts for a 2019 Kawasaki KX450 Dirt Bike.
The 2019 Kawasaki KX450 features a high-performance, liquid-cooled engine designed for pro-level motocross and reliability under intense conditions. Regular coolant maintenance is critical to prevent overheating, preserve engine longevity, and ensure consistent power delivery throughout your rides. Below is a proprietary step-by-step guide from MotoSport to help you confidently change the coolant in your KX450 while keeping your dirt bike race-ready.
Tools – Supplies Needed
- New coolant (manufacturer-recommended or high-quality equivalent suitable for aluminum engines)
- 10mm socket or wrench
- Phillips screwdriver
- Rags for cleanup
- Drain pan/container
- Funnel
- Distilled water (if you plan to perform a radiator flush)
- Compressed air (optional for complete flush)
Preparation – Safety First
- Allow the engine to cool completely before starting. Hot coolant can cause burns and higher pressure at the radiator.
- Park your KX450 upright on a stand in a well-ventilated area.
- Clean around the radiator cap and drain bolt area to prevent debris from entering the system.
Step-by-Step Coolant Change for the KX450
- Remove the Radiator Cap
Unscrew the radiator cap slowly to relieve any residual pressure. On the KX450, the cap is typically on the right side above the radiator. Removing the cap first allows the coolant to drain thoroughly and prevents vacuum lock in the system.
- Remove the Bleeder Screw
Locate and loosen the radiator bleeder screw, usually situated on the opposite radiator or high point in the cooling system. This step helps prevent fluid from erupting out of the drain at high pressure.
- Drain the Old Coolant
Locate the water pump drain bolt at the bottom of the engine (check near the right engine case/lower radiator hose). Place your drain pan underneath. Remove the bolt using a 10mm socket or wrench. Allow all coolant to fully drain.
- Flush (Optional but Recommended)
For a thorough refresh, reinstall the drain bolt and fill the system with distilled water. Reinstall the radiator cap and briefly run the engine (less than a minute), then repeat the draining process. For deeper cleaning, disconnect lower radiator hoses and carefully use compressed air to clear any remaining coolant without damaging seals.
- Inspect Components
Check the drain bolt washer for wear or deformation and replace if necessary. Inspect hoses for cracks or leaks, and tighten all clamps.
- Reinstall Drain Bolt
Start the drain bolt by hand to avoid cross-threading, then gently tighten with your wrench to manufacturer torque spec.
- Add New Coolant
Using a funnel, slowly pour in your fresh coolant up to the base of the radiator neck. Allow the coolant to settle – you may need to rock the bike side-to-side or squeeze hoses to release trapped air.
- Bleed the System
Tighten the bleeder screw as soon as coolant free of air bubbles emerges. Top off coolant if needed, then reinstall the radiator cap securely (listen and feel for two audible clicks).
- Check for Leaks – Final Steps
Wipe away any spills. Start the engine and let it idle, observing the coolant level and checking for leaks. Inspect the radiator and hose connections. Once cooled, recheck the coolant and top off if necessary.
KX450 Model-Specific Notes
- The 2019 KX450 uses a sophisticated, closed-loop cooling system engineered for racing. Only use coolants that are compatible with aluminum radiators and magnesium engine cases. Many riders and technicians recommend using a high-performance, pre-mixed, non-silicate coolant for maximum protection.
- Always keep track of coolant level during long motos or after hard rides, as extreme conditions can cause heat spikes.
- Valve cover, radiator hoses, and temperature sensors are relatively accessible but handle with care to avoid damaging lightweight magnesium and aluminum parts.
Keeping your KX450's cooling system fresh is one of the easiest ways to ensure peak performance on the track or trail. A regular coolant change every one to two riding seasons – or sooner after hard use or races – will help your Kawasaki deliver consistent power and reliability for years to come.
Related Shopping Categories
Shop Radiators for a 2019 Kawasaki KX450 Dirt Bike.
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Shop Temperature Sensors for a 2019 Kawasaki KX450 Dirt Bike.
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Shop Radiator Hoses for a 2019 Kawasaki KX450 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.