How to Change the Coolant in a 2019 Yamaha YZ250

Shop parts for a 2019 Yamaha YZ250 Dirt Bike.

Regularly changing the coolant in your 2019 Yamaha YZ250 is essential to retain peak engine cooling, prevent corrosion, and keep your performance up during demanding rides. The process is straightforward, but paying attention to the right steps – and specific needs of the YZ250 – will make the difference between a routine service and a frustrating hassle. Here is MotoSport–s expert step-by-step guide to refreshing your YZ250–s coolant system.

What Makes the 2019 YZ250 Unique?

The YZ250 is a legendary 2-stroke dirt bike known for its power delivery, reliability, and straightforward maintenance. With its aluminum engine construction, choosing the right coolant is even more crucial to prevent corrosion and overheating. Yamaha recommends using a high-quality ethylene glycol anti-freeze with corrosion inhibitors, mixed 50% with soft or distilled water for optimal protection.2

Recommended Tools & Supplies

  • New coolant (ethyl glycol based with anti-corrosion additives for aluminum engines)
  • Distilled or soft water (if mixing your own)
  • Drain pan or container
  • Ratchet with socket (for drain bolt)
  • Torque wrench
  • Shop towels
  • Funnel

Step 1: Let the Bike Cool Completely

Never open the radiator cap when the engine is hot. Allow your YZ250 to cool down completely before starting this process.

Step 2: Remove the Skid Plate (if equipped)

This clarifies access to the drain bolt and helps prevent making a mess. It–s not strictly necessary, but recommended for a clean job.

Step 3: Drain the Old Coolant

  • Place your drain pan under the engine.
  • Locate the coolant drain bolt on the water pump cover (typically on the right side of the engine, lower area).
  • Remove the radiator cap to allow air in, then remove the drain bolt and let the coolant drain completely.2

Step 4: Flush the Cooling System

  • To help prevent scale and sediment build-up, pour some clean tap water through the system.2
  • You may wish to reinstall the drain bolt (finger tight) to let water sit and dissolve deposits, then drain again.
  • Blow excess water out with compressed air, or let it air dry if possible.

Step 5: Reinstall the Drain Bolt

  • Replace the copper washer if it shows signs of wear or deformation.
  • Tighten the drain bolt to 10 Nm (7.2 ft–lb) using a torque wrench.2

Step 6: Add New Coolant

  • Using a funnel, slowly fill the radiator to the top with your premixed coolant (50% high-quality ethylene glycol anti-freeze with soft or distilled water for aluminum engines).
  • The system takes approximately 1.2 L (1.27 US qt).2

Step 7: Bleed the System

  • Gently rock the bike and squeeze the radiator hoses to release trapped air bubbles.
  • Allow the coolant to settle, then top off as needed.
  • Temporarily start the engine, let it idle until it warms up, then shut it off and recheck the coolant level.3

Step 8: Reinstall the Radiator Cap

Once the coolant is at the correct level and no bubbles rise, securely close the radiator cap.

Step 9: Inspect for Leaks & Final Check

  • Start the engine and run it briefly
  • Examine the drain bolt, hoses, and radiator for any signs of leaks
  • Reinstall the skid plate if removed

Quick Tips Specific to the 2019 YZ250

  • Always use coolants safe for aluminum engines to prevent corrosion and internal damage.
  • Check the radiator cap–s seal and spring every season.
  • Inspect hose connections; cracks or swelling mean they should be replaced for reliability.
  • Change coolant every year or 40-50 hours of engine use, whichever comes first.3

Staying on top of coolant maintenance protects your 2019 YZ250–s engine investment and ensures maximal performance & reliability on any terrain. Questions about coolant, gaskets, or hose upgrades? Shop parts for a 2019 Yamaha YZ250 Dirt Bike.

Related Shopping Categories

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Shop Radiator Hoses for a 2019 Yamaha YZ250 Dirt Bike.

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.