How to Change the Coolant in a 1993 KTM 300MXC

Shop parts for a 1993 KTM 300MXC Dirt Bike.

Routine coolant changes are key for reliable performance and long engine life in your 1993 KTM 300MXC. Unlike modern four-strokes, this two-stroke legend uses a simple, robust liquid cooling system – but keeping it properly maintained prevents overheating and internal engine damage. Below is a step-by-step guide developed just for MotoSport riders who demand the best from their bikes.

Everything You Need

  • New coolant (engine ice, propylene glycol-based, or as recommended)
  • Distilled water for flushing (do not use tap water)
  • Drain pan
  • 8mm or 10mm socket (verify by checking your bike)
  • Rags and gloves
  • Funnel
  • Optional: Air nozzle or low-pressure compressed air for thorough flushing

Step 1: Prepare the 300MXC

Let the bike cool fully. Place your KTM upright on a stand, ideally with the front end raised slightly – about 19 inches if possible. This ensures trapped air can escape during bleeding, reducing the risk of future overheating. Secure your work area so the motorcycle cannot roll or tip over.

Step 2: Drain the Old Coolant

  • Remove the radiator cap carefully to relieve any pressure in the system.
  • Locate the drain bolt on the water pump cover (bottom right side of the engine case).
  • Position your drain pan underneath and remove the drain bolt to allow all old coolant to flow out.
  • Some 300MXC models may have a small bleed screw on the cylinder head – loosen it to further help draining and air release.

Step 3: Flush the System

  • Replace the drain bolt temporarily and fill the radiator with distilled water only (never use tap water which can leave mineral deposits).
  • Run the engine briefly (1 to 2 minutes, not to operating temperature) to circulate the water and help remove old coolant residues.
  • Shut off the bike, allow to cool, then drain again using the same process.
  • Repeat flushing until water runs clear from the drain – this may take several cycles for neglected or high-mileage bikes.

Step 4: Fill with New Coolant

  • Reinstall the drain bolt (with a fresh washer if needed) and tighten securely.
  • With the radiator cap off, slowly fill the radiator with your chosen engine coolant. The system requires roughly 1.2 liters (1.3 quarts).
  • If your bike has a cylinder head bleed screw, open it slightly as you fill – close it once coolant flows free of air bubbles.
  • Fill until coolant sits at the bottom of the radiator neck.

Step 5: Bleed the Cooling System

  • With the bike still elevated in the front, gently rock it side to side to dislodge any trapped air.
  • Install the radiator cap securely.
  • Start the engine and let it run at idle for several minutes, then shut it off and let it cool.
  • Carefully remove the cap and inspect the coolant level; top off if necessary. Repeat once for a thorough bleed.

1993 KTM 300MXC Model Notes

  • The power-valve two-stroke design means keeping coolant fresh and air-free is even more crucial than on a modern four-stroke.
  • Check radiators, hoses, and clamps for leaks or age-related damage. OE parts are available through MotoSport if needed.
  • Always use a 50/50 mix of high-quality coolant and distilled water unless using a pre-mixed solution.
  • Be sure to check coolant levels before every ride, especially if riding in tough, slow trail conditions where overheating risk is highest.

Wrap-Up

That's all it takes to keep your 1993 KTM 300MXC running cool, crisp, and ready for the next ride. Regular coolant service saves you from costly repairs and keeps performance at its peak—so put coolant checks on your regular maintenance schedule and purchase all your 300MXC parts exclusively at MotoSport.

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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.