How to Change the Coolant in a 2017 KTM 300XCW: The MotoSport Guide

Shop parts for a 2017 KTM 300XCW Dirt Bike.

Changing the coolant in your 2017 KTM 300XCW is a key part of regular maintenance that keeps your engine temperature in check even on hard rides. Unlike many modern four-strokes, this two-stroke relies on a straightforward cooling system, but there are specific KTM quirks to keep in mind–especially when it comes to bleeding air and managing the delicate T-piece. This exclusive MotoSport step-by-step guide will walk you through the process and highlight what matters most to 300XCW owners.

What You Will Need

  • Fresh motorcycle-ready coolant (ETHYLENE GLYCOL-BASED; silicate-free recommended for KTM)
  • Socket wrench set
  • Flat-head screwdriver
  • Drain pan
  • Rags or paper towels
  • Funnel
  • Torque wrench (recommended)
  • Optional: replacement seal ring for drain bolt

Preparation

  • Make sure the engine is completely cool before you start to avoid burns and pressure-spray from hot coolant.
  • Position the bike upright on a level surface–a stand works best.
  • Secure the work area, and be prepared to clean any spills, as coolant is toxic to pets and the environment.

Step 1: Remove the Skid Plate (if equipped)

  • You will need clear access to the water pump located on the lower right side of the engine. Remove any skid plates or guards as necessary.

Step 2: Drain the Old Coolant

  • Locate the drain bolt on the water pump cover. On all 300XCW models, this is typically a 6mm or 8mm bolt at the base of the pump.
  • Place your drain pan under the bolt, then remove the radiator cap to allow air to enter and help the coolant flow out quickly.
  • Remove the drain bolt completely and let the coolant empty into your drain pan. Gently tip the bike side to side if needed to ensure both radiators empty fully–the KTM 300XCW runs dual rads connected in parallel, so keep an eye that both are draining evenly.

Step 3: Inspect the System

  • Check the drained coolant for excessive debris or oil contamination. Sludge or milky color may indicate a leak elsewhere in the system.
  • Look at the stock coolant T-piece between the rads; this is often a weak point on older 300XCWs and can crack. Upgrade to a silicone T-piece for improved reliability if the original shows any sign of damage.

Step 4: Reinstall the Drain Bolt

  • Replace the drain bolt, preferably with a new seal ring if available. Hand-tighten, then torque to manufacturer specs if possible (usually around 6 Nm).

Step 5: Refill With Coolant

  • With the bike upright, slowly fill the radiator with new coolant up to the bottom of the filler neck–your bike takes approximately 1.2 liters (1.3 qt.).
  • To help air escape, gently rock the bike, or squeeze/press the main radiator hoses a few times. Some riders gently tilt the bike side to side to help bubbles rise up and out.
  • On KTM 250/300 engines, it's recommended to elevate the front wheel (about 16–19 inches) to make sure trapped air doesn't collect at the highest points in the cylinder or radiators. This is especially important for the 2017 model, which can be difficult to bleed completely if left flat.

Step 6: Bleed Air From the System

  • The 2017 300XCW includes a bleeder screw on top of the cylinder head.
    • Loosen the screw until coolant flows out steadily without bubbles, then retighten. This ensures trapped air has escaped and the cooling system is efficiently filled.
  • Top off coolant if the level has dropped, then reinstall the radiator cap securely.

Step 7: Final Steps – Ready to Ride

  • Start the engine and run at idle until it reaches normal temperature. Shut it off and allow to cool.
  • Remove the radiator cap and check the coolant level again, topping off if needed.
  • Reinstall any guards or skid plates that were removed.
  • Dispose of old coolant safely and legally–never pour it down the drain or onto the ground.

Important Model-Specific Notes for the 2017 KTM 300XCW

  • The OEM radiator T-piece is a weak spot–the stock metal is known to become brittle and leak after hard use or a tip-over. Inspect it regularly and consider upgrading.
  • Check for split hoses and weak clamps, as KTM two-stroke cooling systems can build modest but sudden pressure surges under hard riding.
  • Bleeding the cooling system thoroughly is crucial. Air pockets can cause overheating, especially on steep or technical terrain common for XCW riders. Always use the cylinder head bleeder even if it seems unnecessary.
  • Never mix coolant types (green, red, orange): always fully flush the old type before switching to a new formula to avoid chemical incompatibility and possible clogs.

With these steps, your 2017 KTM 300XCW cooling system will be ready to handle anything the trail, woods, or track can throw at it. Proper care means more rides–and less worry about overheating issues mid-ride. For all the OEM gaskets, seal rings, or even a silicone radiator T-piece upgrade, MotoSport.com has you covered.

Related Shopping Categories

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Shop Radiator Hoses for a 2017 KTM 300XCW 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.