How to Change the Coolant in a 2020 Yamaha YZ250F: Step-by-Step Guide

Shop parts for a 2020 Yamaha YZ250F Dirt Bike.

Keeping your 2020 Yamaha YZ250F's cooling system fresh is critical for optimal performance and engine longevity. Here is a MotoSport-exclusive guide tailored specifically for your YZ250F, factoring in unique considerations for this high-revving, race-tuned machine.

What You Will Need

  • Fresh coolant (preferably a high-performance coolant formulated for aluminum engines)
  • 8mm socket or wrench
  • Drain pan or bucket
  • Funnel (optional)
  • Distilled water (if you want to flush)
  • Clean rags
  • Gloves and safety glasses (recommended)

Preparation – Before You Start

  • Ensure the engine is cool to prevent burns from hot coolant or pressurized steam.
  • Move your YZ250F onto a stable, level surface.
  • Remove the right-side shroud panel if better access to the radiator cap is needed.

Step 1: Locate and Remove the Radiator Cap

  • Find the radiator cap on the left side of the bike, just above the radiators—the YZ250F's design tucks the cap near the air filter box for compactness.
  • Remove the cap slowly to release any residual pressure.

Step 2: Drain the Old Coolant

  • Locate the coolant drain bolt on the right side of the cylinder (often below the water pump housing).
  • Place your drain pan under the bolt.
  • Use an 8mm socket to remove the bolt and allow the coolant to fully drain.
  • Open the radiator cap (if not already removed) to let air in, speeding up the draining process.
  • Inspect the sealing washer on the drain bolt; replace if worn or damaged to prevent leaks.

Step 3: Optional Flush

  • If you see substantial debris or old residue, flush the system with distilled water—refill, run briefly (do not overheat), and drain fully.

Step 4: Reinstall the Drain Bolt

  • Reinstall the clean drain bolt with washer and torque to manufacturer spec (typically 7–9 Nm).

Step 5: Refill with New Coolant

  • Using a funnel, slowly pour fresh coolant into the radiator filler neck until full.
  • Gently rock the bike side-to-side to help purge air pockets.
  • Top off again if the level drops after purging air.

Step 6: Bleed Air & Inspect for Leaks

  • With the radiator cap off, start the engine and idle for a short time. This circulates coolant and helps push out trapped air.
  • Shut off the engine and check the coolant level; top off if necessary.
  • Inspect all fasteners and hoses for leaks.
  • Install the radiator cap securely.

Step 7: Reassemble & Clean Up

  • Reinstall any panels or shrouds removed for access.
  • Wipe away any spilled coolant, especially from painted or metal surfaces.
  • Dispose of old coolant properly—never pour it down household drains.

YZ250F Model-Specific Notes

  • The 2020 YZ250F uses a compact, twin-radiator, liquid-cooled system designed for high temperatures and race use. Always use coolants compatible with modern aluminum radiators to prevent internal corrosion.
  • Inspect the radiator cap rubber seal and pressure relief for damage—a weak cap can lead to boil-over and loss of coolant under hard riding.
  • Under extreme riding (motocross speed, frequent clutch work), more frequent coolant changes may be needed. Yamaha recommends checking after every few races or approximately every 60 hours of use for hard-ridden machines.

Pro Tips

  • Never substitute automotive coolant without checking compatibility; some silicate-based coolants can damage aluminum engine parts.
  • Coolant should appear clean (green, blue, pink, or clear, depending on formulation), not brown or cloudy.
  • Keep a record of coolant changes for your maintenance log.

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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.