How to Change the Coolant in a 2023 GAS GAS EX 450F

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Routine coolant changes are a key part of keeping your 2023 GAS GAS EX 450F running strong and temperature-controlled, whether you're blasting trails or racing on the circuit. This guide from MotoSport walks you step-by-step through a complete coolant change – highlighting the nuances of your cutting-edge fuel-injected 450F.

What You'll Need

  • Fresh, high-quality motorcycle coolant/antifreeze (consult your owner's manual for recommended type and capacity)
  • Socket set or boxed-end wrenches
  • Drain pan
  • Funnels (small and medium size recommended)
  • Clean shop rags
  • Phillips screwdriver
  • Gloves and eye protection

Before You Begin

  • Let your engine cool completely before servicing. Hot coolant can cause serious burns.
  • Work in a ventilated area and avoid allowing coolant to contact skin, eyes, or the environment.
  • Keep the motorcycle upright using a stand.

Step-by-Step Coolant Change

  1. Remove the Seat and Fuel Tank (if required)
    On the EX 450F, the radiator cap is typically accessed by first removing the seat, then unbolting or unclipping the fuel tank. This clears access to the radiator neck and cap.
    Carefully disconnect the tank vent line and the fuel connection if removing the tank entirely.
  2. Remove the Radiator Cap
    Open the radiator cap slowly to relieve any pressure. NEVER take off the cap when the engine is hot.
  3. Drain the System
    • Locate the coolant drain bolt on the water pump cover (typically on the right side of the engine, near the lower radiator hose connection).
    • Place your drain pan beneath it and remove the bolt.
    • Allow the coolant to fully drain. Slightly tilting the bike may help remove trapped fluid.
    Tip: Loosening the radiator cap fully helps the system drain faster.
  4. Flush (Optional, but recommended)
    If dirt or residue is visible, use distilled water to flush out the old coolant completely. Pour in water, reinstall the drain bolt, and run the engine briefly (with the radiator cap on). Let cool, then drain again.
  5. Reinstall/Inspect the Drain Bolt
    Inspect the drain bolt and washer for wear. Tighten the drain bolt to factory torque spec (double-check your owner's manual for the specific number).
  6. Refill the Coolant
    • Using a funnel, pour your new coolant into the radiator neck. Most EX 450F models use around 1.2 - 1.3 liters, but always verify the spec for your 2023.
    • Fill until the coolant is at the bottom of the filler neck.
  7. Bleed the Cooling System
    The EX 450F may feature a bleed screw near the thermostat or a high point in the coolant system.
    • Loosen the bleed screw while filling until coolant flows without air bubbles, then retighten.
    • This helps eliminate trapped air that could cause overheating.
  8. Reinstall the Radiator Cap and Components
    Carefully reinstall the radiator cap, followed by the fuel tank and seat.
  9. Run the Engine & Double-Check
    Start the engine and let it idle for several minutes. Watch the temp gauge and check for leaks or overflowing coolant. Shut off, let cool, and recheck the coolant level – top off if needed.

EX 450F Owner Notes

  • The 2023 EX 450F shares technology with KTM and Husqvarna competition bikes, so always expect premium-grade components and high cooling efficiency.
  • This model is engineered for aggressive enduro riding, so keeping the cooling system perfectly maintained helps prevent overheating in technical sections and slow-speed riding.
  • Use only coolants that are compatible with aluminum components to avoid internal corrosion.
  • Inspect your radiator cap and hoses during service. Pressure loss is a common source of overheating.
  • If you run performance or aftermarket radiators, check for any special fill or bleed instructions.

Service your GAS GAS EX 450F cooling system regularly for extended engine life, improved power delivery, and top confidence on the trail or course.

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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.