How to Change the Coolant in a 1990 Suzuki DR250

Shop parts for a 1990 Suzuki DR250 Dirt Bike.

Maintaining your 1990 Suzuki DR250 is key to keeping your dirt adventures going strong, and one crucial aspect is changing the coolant. This simple job ensures your engine stays at optimal temperature and resists corrosion, especially during those tough trail sessions. Here–s a step-by-step guide on how to change the coolant – with specific tips for the DR250 owner.

What You Need

  • Fresh motorcycle engine coolant compatible with aluminum engines (ethylene glycol-based is standard)
  • Distilled water
  • Clean drain pan
  • 8mm socket or wrench
  • Screwdriver (for radiator shroud removal, if installed)
  • Funnel
  • Protective gloves and rags

Step 1: Allow the Bike to Cool

Make sure the DR250 is completely cool before starting. Opening the cooling system while hot can cause burns from hot coolant under pressure.

Step 2: Access the Cooling System

  • Remove the seat and tank shrouds if they block access to the radiator.
  • Locate the radiator cap on the left side – always open it slowly to release any residual pressure.

Step 3: Drain the Old Coolant

  • Place your drain pan under the water pump (bottom right side of the engine).
  • Locate and remove the coolant drain bolt on the pump using the 8mm wrench. (Some models may also use a drain plug on the side of the cylinder.)
  • After draining, lean the bike gently left and right to ensure complete evacuation of old coolant.
  • Remove the radiator cap fully to let air in and improve draining efficiency.

Step 4: Flush with Distilled Water

  • Reinstall the drain bolt gently (do not overtighten).
  • Add distilled water to the radiator using a funnel. Avoid tap water due to mineral deposits.
  • Run the engine for about 1–2 minutes with the radiator cap off (do not let it overheat).
  • Shut down, remove the drain bolt again, and flush out the water.
  • Repeat this step until the drainage runs clear.

Step 5: Add New Coolant

  • Reinstall and snug the drain bolt.
  • Fill the radiator slowly with new coolant up to the base of the filler neck.
  • If your bike has a coolant overflow reservoir, top up to the "Full" mark.

Step 6: Bleed Air from the System

  • Start the bike with the radiator cap off and let it idle – air bubbles will escape as the thermostat opens. You may notice the coolant level drop suddenly; top off if needed.
  • Once bubbling stops and coolant stabilizes, replace the radiator cap securely.

Step 7: Final Checks

  • Run the engine until fully warm and allow to cool completely.
  • Recheck coolant levels – top off if needed. Inspect for leaks around the drain bolt and hoses.

1990 Suzuki DR250 Specific Notes

  • The DR250–s air-cooled cylinder head and aluminum radiator require an aluminum-compatible coolant for corrosion prevention.
  • Early DR250s are known for their simple, reliable cooling systems without electric radiator fans, so precise coolant level and condition are vital on longer rides.
  • Inspect the radiator fins and cap for damage or corrosion – these can contribute to overheating, especially as the bike ages.
  • If you regularly ride in muddy or sandy environments, consider flushing your cooling system more often to avoid blockages in the radiator or passages.

Proper Disposal

Never dump used coolant down the drain or onto the ground. Bring it to a local waste facility that accepts automotive fluids.

Staying on top of coolant changes will ensure the legendary DR250 reliability lives on, mile after mile. Proper maintenance now pays off on the trail, where the DR250 thrives.

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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.