How to Change the Coolant on a 2015 KTM 350EXCF

Shop parts for a 2015 KTM 350EXCF Dirt Bike.

Maintaining optimal engine temperature and long-term reliability on your 2015 KTM 350EXCF starts with fresh coolant. This routine task ensures your dirt bike keeps performing on the trails without overheating or internal corrosion. The steps below will walk you through a clean and effective coolant change while highlighting what makes your KTM 350EXCF unique.

What You Need

  • Coolant compatible with aluminum engines (avoid silicate-based formulas)
  • Distilled water (for flushing)
  • Socket set (8mm typically fits the coolant drain bolt)
  • Catch pan or container
  • Funnel
  • Gloves and eye protection
  • Torque wrench (recommended for reassembly)

Step-by-Step Instructions

1. Let the Engine Cool

Avoid burns–always make sure the engine is completely cool before you start. Pressure in the cooling system can cause hot coolant to spray if you open the radiator cap too soon.

2. Remove the Skid Plate (if equipped)

Some KTM 350EXCF bikes are fitted with a skid plate that can block access to the water pump area. Remove it with your socket set for easier access.

3. Release the Pressure

Slowly unscrew the radiator cap to release any residual pressure, then remove the cap completely.

4. Locate and Remove the Coolant Drain Bolt

The coolant drain bolt is usually on the lower water pump cover on the right side of the engine. Position your catch pan beneath, then remove the bolt with your 8mm socket. Coolant will drain from the system–giving the bike a slight lean helps move out additional fluid.

5. Flush the Cooling System

Once drained, temporarily reinsert the drain bolt, fill the system with distilled water, loosely refit the cap, and start the engine. Let it idle for about five minutes, then shut it off and let it cool. Drain the water just like you did the coolant. Repeat until the fluid runs clear to remove all old coolant.

6. Replace the Drain Bolt

Reinstall the drain bolt and torque it to the manufacturer's spec (typically around 6 Nm but always check your owner's manual for confirmation).

7. Pour in New Coolant

With the drain bolt securely fitted, use a funnel to fill the radiator with fresh coolant. Add slowly to avoid air pockets. Fill up to the base of the radiator neck.

8. Bleed Air from the System

Tip the bike side to side gently to release trapped air. Some KTM EXCF models include a bleed screw on the cylinder head or top of the radiator–loosen this briefly to vent any remaining air, then retighten.

9. Refit the Radiator Cap and Skid Plate

After verifying fluid level and air removal, refit the radiator cap securely. Replace your skid plate if removed.

10. Final Check

Start the bike and let it idle. The coolant may drop after circulating through the system–turn off the bike, let it cool, and top off as needed. Check for leaks at the water pump and drain bolt areas.

Special Notes for 2015 KTM 350EXCF Owners

  • The EXCF features a highly responsive cooling system; always use coolant specified for high-performance aluminum engines to avoid corrosion and premature wear.
  • Inspect radiator hoses and the cap for wear–failure or cracks are a common source of future leaks.
  • The 350EXCF's cooling system is compact, making air pockets more likely–always double-check air removal for consistent performance.
  • If your bike has seen muddy or wet riding, consider checking the radiator fins for debris buildup during this process.

Stay ahead of major engine repairs by making coolant changes part of your regular KTM 350EXCF maintenance routine. A simple afternoon job pays off with every smooth, cool-running ride.

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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.