How to Change the Coolant in a 1993 KTM 250EXC

Shop parts for a 1993 KTM 250EXC Dirt Bike.

Changing your coolant is essential maintenance for your 1993 KTM 250EXC to keep it running cool during demanding rides. Here is a detailed, proprietary MotoSport guide for this specific model, along with notes relevant to the 250EXC's unique requirements.

What Makes the 1993 KTM 250EXC Special?

The 1993 KTM 250EXC features a two-stroke engine with a separate transmission case and a liquid cooling system equipped with dual radiators. These bikes are known for their durability and performance, but overheating – especially in technical terrain or race conditions – can be problematic if the cooling system is not maintained. This year of the 250EXC used a relatively small coolant volume, making proper venting and coolant quality crucial for longevity and performance.

Tools and Supplies You Need

  • Fresh coolant (use a 40% coolant – 60% distilled water mix, or premixed high-performance motorcycle coolant)
  • Drain pan
  • Phillips screwdriver or appropriate socket wrench
  • Shop rags
  • Funnel
  • Gloves (recommended)

Step-by-Step Coolant Change Procedure

  1. Ensure the Engine is Cool.
    Never open the radiator cap or start the procedure with the engine hot – hot coolant can cause serious burns.
  2. Remove the Seat and Radiator Shrouds as Needed.
    This gives you clear access to the radiator cap and mounting hardware if required.
  3. Remove the Radiator Cap.
    Twist the cap off slowly to relieve any residual pressure.
  4. Locate and Remove the Drain Screw.
    On the 250EXC's right-side water pump area, find the coolant drain screw (usually 8 mm bolted) at the lowest point. Place the drain pan underneath, then remove the screw. Allow the old coolant to fully drain.
  5. Flush if Needed.
    If the coolant is especially dirty, you can flush with distilled water. Replace the drain screw and repeat the fill-and-drain step until clear water runs out. Tighten the drain screw securely after the last drain.
  6. Refill the Cooling System.
    • Make sure the drain screw is tight before refilling.
    • Pour roughly 0.5 liters (0.13 US gallons) of the coolant mix into the left radiator until you see coolant above the radiator fins (about 10 mm above the fins is optimum).
    • KTM recommends to then remove the air bleed screw on the right radiator and lean the bike to the right about 30 degrees. Slowly fill until coolant emerges free of bubbles, then immediately reinstall the screw to keep air out.
  7. Bleed Out Trapped Air.
    Gently shake or tap the radiator hoses, or compress and release, to dislodge any air pockets that may have formed.
  8. Check and Top Off.
    With the bike upright, verify the coolant level is still at the proper height above the left rad's fins. Top off if needed.
  9. Reinstall the Cap and Bodywork.
    Secure the radiator cap and any bodywork you removed earlier.
  10. Test Run and Final Check.
    Start the bike and let it idle until warm. Watch the coolant level through the cap or overflow. After it cools, remove the cap and confirm the level is still correct. Top off again if necessary.

Key Tips for the 1993 KTM 250EXC

  • Always use high-quality engine coolant. Inadequate or poor-grade coolant can cause corrosion and premature water pump seal wear.
  • Do not mix different coolant types. If you are switching from conventional to silicate-free or a race coolant, thoroughly flush the system first.
  • Check hoses and radiator seals for leaks or wear. The 1993 model's cooling system is robust, but with age, rubber parts can become brittle.
  • Replace O-rings and gaskets whenever you see signs of weeping or leaks around fittings and drain plugs – these are known to harden with age.

Staying on top of coolant maintenance on your 1993 KTM 250EXC will help avoid overheating on the trail and ensure reliable performance for years – and if you need OEM or upgrade parts, Shop parts for a 1993 KTM 250EXC Dirt Bike.

Related Shopping Categories

Shop Radiators for a 1993 KTM 250EXC Dirt Bike.

Shop Coolant for a 1993 KTM 250EXC Dirt Bike.

Shop Temperature Sensors for a 1993 KTM 250EXC Dirt Bike.

Shop Tools for a 1993 KTM 250EXC Dirt Bike.

Shop Radiator Hoses for a 1993 KTM 250EXC 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.