How to Change the Coolant in a 2018 Yamaha YZ250F: MotoSport Guide
Shop parts for a 2018 Yamaha YZ250F Dirt Bike.
Routine coolant changes are essential for the performance and longevity of your 2018 Yamaha YZ250F. The aluminum engine on this model is susceptible to corrosion if not maintained with high-quality coolant, and proper change intervals help prevent overheating and internal engine wear. This proprietary MotoSport guide ensures you handle the process with ease while keeping your bike ready for the track or trail.
What Makes the 2018 YZ250F Coolant System Unique?
The 2018 YZ250F features a liquid-cooled, aluminum head engine. Always use ethylene glycol anti-freeze formulated for aluminum engines. Using only distilled water is permissible in emergency situations, but adjust the antifreeze mix as soon as possible to restore protection. Never use tap water long-term, as it promotes scaling and corrosion in the radiator and cooling circuit.
Tools & Supplies Needed
- 8mm socket or wrench (for drain bolt)
- Drain pan or container
- Funnel
- Fresh high-quality coolant compatible with aluminum engines (see owner's manual, but 1.0 L is required)
- Compressed air (optional, for drying system after flushing)
- Protective gloves & eye protection
Step-by-Step Guide: Changing the Coolant
-
Ensure a cool engine
Always start with the bike completely cooled down to avoid serious burns when opening the radiator cap or drain bolt. -
Access the radiator cap
Remove the seat and left-side panels to expose the top of the radiator. Loosen (but do not fully remove yet) the radiator cap to relieve pressure. -
Drain the old coolant
Position a drain pan under the water pump coveron the right side, locate the coolant drain bolt (8mm head). Remove the bolt and let the old coolant flow into the pan. Remove the radiator cap completely to expedite draining.
Tip: Place the bike upright on a stand for full draining. Observe for flow from both radiators. -
Flush the cooling system
Reinstall the drain bolt temporarily, fill the system with distilled water, and run the engine for 2-3 minutes with the radiator cap off. Allow to cool, then drain again. Repeat until only clear water drains out.
Compressed air can help expel residual water. -
Inspect & clean
Wipe down the outside of the radiator and hoses. Inspect for hose fatigue, leaks at joints, and check the condition of your radiator cap. -
Refill with new coolant
Reinstall and tighten the drain bolt (do not overtighten). Using a funnel, pour coolant into the radiator until just below the filler neck. Capacity for the 2018 YZ250F is 1.0 liter.
Fill slowly to prevent air pockets. -
Bleed air from the system
With the radiator cap off, briefly run the engine to circulate new coolant. Tap hoses gently to dislodge trapped air. Top off coolant if necessary and install the cap. -
Check for leaks & final inspection
Start and run the bike until normal operating temperature. Inspect around the drain bolt, hoses, and radiator cap for leaks.
Allow the bike to cool and recheck coolant leveltop off if needed.
Notes for 2018 YZ250F Owners
- This model's radiator and cooling passages are relatively narrowdo not use additives with particulates or sealants that could cause blockages.
- Routine inspection of the radiator fins for damage is recommended.
- Only use coolants specified for aluminum motorcycle engines to prevent damage and maximize cooling efficiency.
- Never open the radiator cap on a hot engine—pressure release can cause severe burns.
- Dispose of old coolant according to local environmental guidelines, as antifreeze is hazardous to pets and wildlife.
Keeping your 2018 YZ250F's cooling system healthy is a critical part of your maintenance schedule. Following these steps ensures optimal performance whenever you ride.
Related Shopping Categories
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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.