How to Change the Coolant in a 2025 GAS GAS EX 350F: MotoSport Guide

Shop parts for your ride now!

Changing the coolant in your 2025 GAS GAS EX 350F is an essential part of routine maintenance to keep its high performance, cross-country engine running cool and reliably. This guide covers the best practices for a coolant service on this specific model – including tips unique to the EX 350F’s advanced cooling system and chassis layout.

Tools & Supplies Needed

  • Phillips and flathead screwdrivers
  • Socket set (usually 8mm or 10mm for panels and drain bolt)
  • Drain pan
  • Pre-mixed motorcycle coolant (propylene glycol-based or type approved by the manual)
  • Fresh sealing washer (recommended for drain bolt)
  • Distilled water for rinsing (do not use tap water)
  • Shop rags
  • Protective gloves and eyewear

Step-by-Step Coolant Change Procedure

  1. Ensure Safety and Cool Engine
    Confirm the engine is completely cool before starting. The EX 350F’s compact frame and high compression engine mean coolant can reach very high temperatures quickly. Never open the radiator cap on a hot engine—pressure can cause serious burns.
  2. Remove Plastics and Tank Shrouds
    Carefully remove the side panels and radiator shrouds to expose the radiator. While the EX 350F features quick-release fasteners, set aside all hardware so reassembly is straightforward.
  3. Locate and Open Radiator Cap
    The radiator cap is on the left side. Open it slowly to relieve any residual pressure. Set the cap aside on a clean rag.
  4. Drain the Coolant
    Place the drain pan underneath the water pump area. The drain bolt is typically located at the lowest point of the water pump cover on the right side. Remove the bolt using the appropriate socket. Allow all coolant to drain completely.
    Tip: Tilting the bike gently from side to side helps release trapped fluid. Dispose of the old coolant at an approved recycling center.
  5. Flush the System (Recommended)
    For thorough cleaning, pour distilled water into the radiator, reinstall the drain bolt, and run the engine briefly (cap off, do not overheat). Shut off, allow to cool, and drain. Repeat until only clear water exits. Never use tap water. 
  6. Reinstall the Drain Bolt
    Fit a new sealing washer on the drain bolt. Torque the bolt to manufacturer specification (refer to owner’s manual for correct value).
  7. Add New Coolant
    Fill the radiator with your approved coolant up to the filler neck. The EX 350F’s system usually requires about 0.8–1.0 liters, but check your manual for current specification.
    Reinstall the radiator cap.
  8. Burp the Cooling System
    With the bike on a level surface, start the engine and briefly run it with the radiator cap removed. Occasionally blip the throttle and gently rock the bike to release trapped air bubbles. Top off coolant as necessary until the level stays consistent.
  9. Check and Fill the Overflow Reservoir
    Fill the overflow tank to the upper line. Check for leaks around the drain bolt and hoses.
  10. Reassemble and Test
    Reinstall all plastics and shrouds. Clean up spilled coolant. Start the engine and ride gently, then recheck the levels after full warm-up and top off if needed.

Notes Specific to the 2025 GAS GAS EX 350F

  • Aluminum Radiators: This bike features lightweight, high-capacity radiators—ensure all bolts are torqued evenly and avoid overtightening to prevent thread damage.
  • High Compression Engine: Regular coolant changes are vital for heat management due to the powerful 350cc, four-stroke engine design.
  • Electrical Connections: The EX 350F uses advanced electronics (Keihin EMS and electric start)—avoid pouring coolant onto wiring harnesses or connectors.
  • Service Intervals: Adhering to recommended coolant change intervals maximizes engine life and prevents expensive repairs from overheating events.

By maintaining your 2025 GAS GAS EX 350F’s cooling system, you’re investing in long-term reliability for intense cross-country rides.

Related Shopping Categories

Shop Radiators for Your Ride

Shop Coolant for Your Ride

Shop Temperature Sensors

Shop Tools

Shop Radiator Hoses for Your Ride

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.