How to Change the Coolant in a 2020 Yamaha YZ250
Shop parts for a 2020 Yamaha YZ250 Dirt Bike.
Proper cooling system maintenance is critical to the legendary performance and reliability of your 2020 Yamaha YZ250. Regularly flushing and replacing the coolant prevents overheating, corrosion, and expensive engine damageespecially when riding in challenging motocross or enduro conditions. The steps below provide a precise, MotoSport-exclusive guide tailored to your MMY YZ250.
What You Need
- High-quality ethylene glycol-based coolant, ideally formulated for aluminum engines, mixed 50/50 with soft or distilled water
- Socket wrench set
- Copper washer (recommended to replace with each service)
- Catch pan or container
- Clean rags
- Safety gloves and eyewear
Step-by-Step Coolant Replacement
- Prepare the Bike
Let the engine cool completely to avoid burns. Place your YZ250 securely on a stand. Never remove the radiator cap when hot due to pressure buildup. - Position a Catch Pan
Place a drain pan directly underneath the engine to capture old coolant. - Remove the Coolant Drain Bolt
Locate the coolant drain bolt at the bottom of the cylinder or water pump. Loosen and remove it, along with the copper washer. Old coolant will begin to drain. To ensure a fast, complete drain, proceed to the next step quickly. - Remove the Radiator Cap
Slowly loosen and remove the radiator cap. This allows air in and lets coolant flow out fully–avoid splashing coolant on painted surfaces; rinse immediately with water if this happens. - Flush the Cooling System
For optimal maintenance, fill the radiator with clean, soft water, reinstall the cap and drain bolt temporarily, and start the engine for one minute. Shut off, let cool, then repeat the drainage process until the flushed-out water runs clear. This step helps eliminate impurities and old coolant residue. - Reinstall the Drain Bolt
Fit a new copper washer on the drain bolt and reinstall. Tighten to Yamaha-specified torque: 10 Nm (7.2 ft–lb). - Refill with Coolant
Pour your premixed coolant into the radiator, filling to the base of the filler neck. The 2020 YZ250 requires approximately 1.2 L (1.27 US qt) of coolant. - Bleed Air from the System
Slightly tilt the bike side-to-side or gently squeeze the radiator hoses to help trapped air escape. Recheck coolant level after air bubbles stop rising. - Replace and Secure the Radiator Cap
Install the cap firmly. - Start and Inspect
Start the engine and let it idle for several minutes with the bike upright. Shut down, let cool, then check the coolant level again. Top off if necessary. - Disposal
Dispose of old coolant responsibly—never pour it down a drain or onto the ground. Used coolant is toxic to people, pets, and wildlife.
YZ250-Specific Tips & Reminders
- The Yamaha YZ250's single-cylinder, two-stroke engine uses an aluminum radiator–always choose a coolant formulated for aluminum components to prevent internal corrosion.
- Inspect for leaks after service, especially at the hose connections, drain bolt, and under the water pump cover.
- Check the coolant level before every ride; rapid loss may indicate a leaking gasket, cracked radiator, or hose issue.
- The YZ250's cooling system is robust, but motocross riders who encounter deep mud or sand tracks should inspect more often. Overheating can be catastrophic on two-strokes.
Keeping the cooling system in top shape ensures your 2020 YZ250 runs strong on every MotoSport adventure.
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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.