How to Change the Coolant in a 2015 Husqvarna TC125

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Routine coolant changes are critical for keeping your 2015 Husqvarna TC125 running at peak performance. The TC125 relies on an efficient liquid cooling system to maintain optimal temperature under demanding motocross conditions. Use only recommended motorcycle coolant – avoid tap water and automotive antifreeze.

Required Tools & Supplies

  • Motorcycle-specific coolant
  • Socket set and hand tools
  • Drain pan
  • Clean rags
  • Funnel
  • Distilled water (for flushing, optional)
  • Gloves and safety glasses

Step-by-Step Guide

  1. Allow the bike to cool completely. Never work on the cooling system with a hot engine—this prevents burns from pressurized hot coolant.
  2. Remove bodywork for access. Take off the right side panel for easier access to the radiator cap and, if necessary, remove the fuel tank to reach the radiator and hose connections.
  3. Locate the radiator cap and coolant drain bolt. The radiator cap sits atop the left radiator. The coolant drain bolt is typically at the lowest point of the water pump cover, on the engine's right side–consult your owner's manual for its precise location.
  4. Position the drain pan. Put a suitable drain pan beneath the water pump area to catch all old coolant.
  5. Remove radiator cap. With the engine cold, unscrew and remove the radiator cap to release any remaining system pressure.
  6. Remove the drain bolt. Unscrew the coolant drain bolt and allow the old coolant to fully drain. Loosening a radiator hose clamp at the bottom can help speed up draining, if needed.
  7. (Optional) Flush the system. To ensure completely clean internals, fill the radiator with distilled water and let it drain again. You may repeat until water runs clear.
  8. Reinstall the drain bolt. Once draining is complete, securely reinstall and hand-tighten the drain bolt. Do not overtighten to avoid damaging the threads.
  9. Fill with new coolant. Using a funnel, slowly pour recommended coolant into the radiator until filled to just below the filler neck. Allow bubbles to escape for a few seconds as you pour.
  10. Bleed air from the system. Gently rock the bike side-to-side to help remove trapped air. Some systems may include a small bleeder screw on the radiator—check and open if present, then retighten after coolant appears.
  11. Reinstall the radiator cap. Ensure the cap is free from damage and fits tightly—replace if bent or worn.
  12. Warm up the engine and re-check the coolant level. Start the bike and let it idle until it reaches normal operating temperature. Shut off the engine, allow it to cool fully, and re-check the coolant level at both the radiator and reservoir. Top up as required.
  13. Inspect for leaks. Carefully look for leaks around drain bolt, hoses, and radiator once the bike has cooled again.

Model-Specific Notes for the 2015 TC125

  • The 2015 Husqvarna TC125 relies on a compact two-stroke liquid cooling system designed for competitive motocross use. Always verify coolant type compatibility, as some performance additives may not be recommended for the TC125's sealing and aluminum components.
  • Check the cooling hoses for signs of aging, wear, or soft spots when performing a coolant change. Hose failures are rare but catastrophic mid-race.
  • The TC125 does not have a thermostat, so thorough bleeding is especially important to avoid hot spots & overheating, especially after a coolant change.
  • Husqvarna recommends regular checks of radiator cap condition—a leaking or weak cap can lead to premature boiling and coolant loss under high load.

Coolant Change Interval

Change the coolant at least once per season, or every twelve months if the bike is stored for extended periods. Inspect before each race or ride in hot weather, as summer competition may accelerate coolant wear.

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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.