How to Change the Coolant in a 1997 KTM 250MXC

Shop parts for a 1997 KTM 250MXC Dirt Bike.

Changing the coolant on your 1997 KTM 250MXC is straightforward but requires attention to a few unique features specific to this model. Keeping your cooling system in top condition prevents overheating and guarantees optimal engine performance every ride. Here’s a step-by-step guide exclusively for MotoSport riders.

What Makes the 1997 KTM 250MXC Cooling System Unique?

The 250MXC uses a liquid-cooling system with twin radiators, optimized for enduro and trail performance. Its 2-stroke engine produces significant heat, making regular coolant changes even more important. This model features specific drain and bleed points, and requires a careful coolant mixture to maintain its alloy components.

Supplies You’ll Need

  • High-quality motorcycle coolant (not automotive coolant – choose one compatible with aluminum engines and radiators)
  • Distilled water (if you’re not using premixed coolant)
  • Drain pan
  • 8mm socket or wrench
  • Funnel
  • Clean rags
  • Torque wrench (recommended)

Step-By-Step Coolant Change Guide

  1. Ensure the engine is cool.
    Never remove the radiator cap on a hot engine. Allow it to sit until it’s safe to touch.
  2. Remove the radiator cap.
    This will help the old coolant drain faster and more completely.
  3. Locate and remove the coolant drain bolt.
    On the 250MXC, the drain screw is found on the lower water pump cover (right side, 8mm bolt located at the lowest point). Place your drain pan underneath and remove the bolt. Let all old coolant drain out.
  4. Flush the system (optional but recommended).
    Add distilled water to the radiator, reinstall the drain bolt lightly, and start the bike for just a minute (do not let it get hot). Drain againrepeat until the water runs clear, which helps remove mineral deposits and debris particular to older cooling systems.
  5. Reinstall and tighten the drain bolt.
    Inspect and clean the sealing surface and O-ring. Torque the bolt to manufacturer specifications (usually hand-tight plus a quarter turn if you don’t have the specific value).
  6. Prepare the coolant mix.
    For this model: mix coolant at 40 percent coolant to 60 percent distilled water, unless using a premixed formula.
  7. Refill the cooling system:
    • Fill the left radiator to the top of the fins.
    • On the right radiator, remove the small bleed screw near the top. Tilt the bike right about 30 degrees.
    • Slowly fill until coolant escapes air-free from the right radiator’s bleed opening.
    • Reinstall the bleed screw quickly to keep out air.
  8. Final top-off:
    Return the bike to an upright position. The coolant in the left radiator should be about 10mm above the fins.
  9. Reinstall the radiator cap.
  10. Start the engine and check.
    Let the bike idle several minutes, checking for leaks and watching the coolant level. Top off again as needed after the engine cools, as air can burp out on first heat cycles.

Important Tips for 1997 KTM 250MXC Owners

  • Check radiator hoses and seals for cracks—replace any that are brittle or swollen, as age-related failures are common in 1990s models.
  • Original radiators can corrode from mineral buildup if water with dissolved solids is used; always use high-purity distilled water.
  • If the engine frequently overheats after a coolant change, check for trapped air in the right radiator and repeat the bleed process.
  • Recommended coolant quantity is approximately 0.50 liters (0.13 US gallons) total for this model.
  • Monitor coolant color and clarity after first rides—cloudy or brown coolant may signal internal corrosion or seal issues.

Routine maintenance of your KTM’s cooling system will keep your 250MXC running cool and strong on every trail. For everything else—from gaskets to replacement radiators—shop parts for a 1997 KTM 250MXC Dirt Bike.

Related Shopping Categories

Shop Radiators for a 1997 KTM 250MXC Dirt Bike.

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Shop Temperature Sensors for a 1997 KTM 250MXC Dirt Bike.

Shop Tools for a 1997 KTM 250MXC Dirt Bike.

Shop Radiator Hoses for a 1997 KTM 250MXC 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.