How to Change the Coolant on a 1989 Yamaha YZ250

Shop parts for a 1989 Yamaha YZ250 Dirt Bike.

Regular coolant changes are essential for keeping your 1989 Yamaha YZ250 running strong, preventing overheating, and protecting the engine's internal components. This step-by-step guide explains how to change the coolant and includes key model-specific tips every YZ250 owner should know.

What You'll Need

  • High quality ethylene glycol-based coolant with anti-corrosion additives for aluminum engines (mix 50/50 with distilled water)
  • Socket wrench set
  • Copper washer (replace if required)
  • Catch container (min. 2 liters capacity)
  • Funnel
  • Clean rags
  • Gloves & safety glasses

Steps to Change the Coolant on a 1989 Yamaha YZ250

  1. Ensure the engine is cool. Never open the radiator cap or drain coolant when hot to avoid burns.
  2. Locate the coolant drain bolt. On the 1989 YZ250, this is found at the lowest point of the water pump cover on the right side of the engine.
  3. Place a container under the engine to catch the old coolant.
  4. Remove the radiator cap. This allows air in, so coolant drains faster and more completely.
  5. Remove the drain bolt and copper washer. Once loose, old coolant will begin to flow out.
  6. Fully drain the system. Tilt the bike side to side to ensure as much coolant as possible empties from radiators and engine cavities.
  7. Flush the cooling system. With the drain bolt out, pour clean distilled water into the radiator to wash out residues. Allow to completely drain. Repeat until clear water exits.
  8. Reinstall the drain bolt with copper washer. Tighten to 10 Nm (7.2 ft–lb).
  9. Pour in fresh coolant. Use a 50/50 mix of ethylene glycol concentrate and distilled water. Total cooling capacity is 1.2 L (1.27 US qt). Fill until the coolant level reaches the bottom of the radiator filler neck.
  10. Bleed air from the system. With the cap still off, gently rock the bike and squeeze the radiator hoses to dislodge trapped air bubbles. Top up if the level drops.
  11. Replace the radiator cap. Make sure it's secured tightly.
  12. Start the engine and let it idle for a few minutes. Check for leaks and watch the coolant level. Turn engine off and allow to cool, topping up as needed.
  13. Properly dispose of old coolant at an authorized recycling or waste center.

Model–Specific Tips for the 1989 Yamaha YZ250

  • Copper washer: Inspect and replace if deformed or damaged to prevent leaks upon reassembly.
  • Weep hole check: Frequently inspect the weep hole under the water pump. Any coolant leakage may indicate a worn mechanical seal or bearing, common on older YZ250s and worth addressing during coolant changes.
  • Coolant mix: Always use a coolant approved for aluminum engines and never straight water, which can cause corrosion and inadequate cooling.
  • Radiator care: Clean debris from the radiator fins and inspect them for bends or clogging to maximize cooling efficiencya critical point for air-cooled 2-stroke engines like the YZ250.

Why Regular Coolant Changes Matter

  • Prevents overheating, especially under demanding riding conditions.
  • Protects engine and radiator from internal corrosion.
  • Extends the life of water pump seals and internal components.

For any replacement radiator parts, gaskets, or coolant supplies, MotoSport stocks a full selection of OEM and aftermarket solutions specifically for your 1989 YZ250. Routine maintenance ensures legendary Yamaha reliability on every ride.

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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.