How to Change the Coolant in a 1997 KTM 300EXC

Shop parts for a 1997 KTM 300EXC Dirt Bike.

If you own a 1997 KTM 300EXC, keeping the cooling system in top condition is essential for engine performance and longevity. Changing the coolant is a straightforward job, but KTM's 300EXC models have some unique characteristics to note. This guide covers everything you need to know to safely and effectively change the coolant, ensuring your bike stays ready for any ride.

Why Changing Coolant Matters

The coolant in your 1997 KTM 300EXC helps regulate engine temperature and prevents overheating. Old or contaminated coolant can reduce cooling efficiency, leading to possible engine overheating and damage. KTM recommends using high-quality coolant for optimal gasket, seal, and aluminum component protection, especially since this is a two-stroke engine designed for off-road use.

What You Will Need

  • Correct replacement coolant (consult your owner's manual or select from MotoSport's KTM 300EXC parts)
  • Distilled water (for flushing if necessary)
  • Container to collect old coolant
  • Wrenches (to remove drain and possibly side cover bolts)
  • Clean lint-free rag

Step-by-Step Guide

  1. Allow the Engine to Cool: Never open the radiator cap or drain plug while the engine is hot to avoid injury from hot coolant or steam.
  2. Secure and Position the Bike: Place the KTM 300EXC upright on level ground and ensure it is stable. This keeps coolant from pooling unevenly in the radiators and ensures a full drain – for these bikes, both left and right radiators must be emptied.
  3. Remove the Radiator Cap: Open the radiator cap to allow air into the system, which helps coolant flow freely when draining.
  4. Locate and Remove the Drain Bolt: The coolant drain bolt is typically located on the water pump cover on the right side of the engine. Place your catch container under the bike and use a wrench to remove the drain bolt (and small washer or seal ring beneath). Allow all coolant to drain completely.
  5. Flush the System (Optional): For extra cleanliness, you can flush the radiators and engine with distilled water. Replace the drain bolt, fill the radiator with distilled water, reattach the cap, run the engine briefly, then drain again. Repeat until clear.
  6. Inspect the Drain Bolt and Seal: Examine the drain bolt and its seal ring (washer). Replace the seal if worn or damaged to prevent leaks on reassembly.
  7. Refit the Drain Bolt: Reinstall the cleaned drain bolt and tighten it to the specified torque as per your owner's manual.
  8. Refill with Coolant: Position the bike upright and slowly fill the radiator with fresh coolant (about 1.2 liters for the 300EXC). When full, stop periodically to let trapped air escape.
  9. Bleed Air from the System: KTM recommends raising or jacking the front wheel slightly to help any trapped air bubbles move to the radiator cap area. Add coolant until it stays topped off and coolant escapes without bubbles.
  10. Reinstall the Radiator Cap: Once completely full and free of bubbles, refit the radiator cap securely.
  11. Start and Warm the Engine: Start the bike and let it idle briefly, then shut off and check the coolant level again. Top up if necessary.
  12. Dispose of Old Coolant: Always dispose of used coolant responsiblynever pour it on the ground or down storm drains.

1997 KTM 300EXC Model-Specific Notes

  • The 1997 300EXC uses a parallel radiator setup, so always ensure both radiators fully drain and refill.
  • A poorly bled system may lead to overheating, especially given the higher thermal loads in aggressive off-road or enduro riding.
  • Inspect coolant hoses for cracks or soft spots, which are common on bikes of this age, and replace if needed.
  • Use coolants compatible with aluminum engines and avoid mixing different coolant colors/types to prevent chemical incompatibility.

When to Change Your Coolant

For most riders, plan to change the coolant at least every two years or after heavy use, such as after a racing season or intense trail riding. Extreme climates may require more frequent changes.

Related Shopping Categories

Shop Radiators for a 1997 KTM 300EXC Dirt Bike.

Shop Coolant for a 1997 KTM 300EXC Dirt Bike.

Shop Temperature Sensors for a 1997 KTM 300EXC Dirt Bike.

Shop Tools for a 1997 KTM 300EXC Dirt Bike.

Shop Radiator Hoses for a 1997 KTM 300EXC 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.