How to Change the Coolant in a 2015 Husqvarna TC85

Shop parts for a 2015 Husqvarna TC85 Dirt Bike.

Keeping the coolant fresh in your 2015 Husqvarna TC85 is critical for peak performance and longevity of your engine, especially given how hard 85cc two-strokes work under race and trail conditions. Follow this MotoSport.com exclusive guide for a proper and safe coolant change tailored specifically to your TC85.

What You Need

  • Gloves and eye protection
  • Phillips or flathead screwdriver
  • Socket set (to remove drain bolt)
  • Coolant compatible with aluminum radiators (premixed or mix with distilled water)
  • Funnel
  • Drain pan
  • Clean rags

Step-by-Step Guide

1. Prepare Your TC85
  • Place the bike securely on a stand in a well-ventilated and level area with a cold engine.
  • Remove side panels or shrouds if needed for easier access to the radiators.
2. Remove Radiator Cap
  • Slowly unscrew the radiator cap to relieve any residual pressure in the system.
3. Drain the Old Coolant
  • Locate the coolant drain bolt, typically found on the lower water pump cover on the right side of the engine.
  • Position your drain pan beneath the drain bolt.
  • Remove the bolt and allow all old coolant to fully drain from both radiators and engine.
  • Some models have a small bleed screw on the cylinder head open this to speed draining and help remove air pockets from the system.
4. Flush the Cooling System (Recommended)
  • Install the drain bolt temporarily and fill the system with distilled water.
  • Start the bike and let it idle briefly (1 minute) to circulate water, then shut down and let cool.
  • Remove the drain bolt again and drain the flush water completely.
5. Reinstall the Drain Bolt
  • Inspect the sealing washer or copper crush washer on the drain bolt; replace if crushed or damaged.
  • Tighten the drain bolt to manufacturer specifications (–10 Nm recommended for similar models).
6. Add New Coolant
  • Insert a funnel into the radiator filler neck and slowly pour in coolant until it reaches the base of the filler neck.
  • If equipped, open the cylinder head bleeder screw slightly until coolant starts to seep out, then close it tightly to release any trapped air.
  • Top off the radiator if needed.
7. Bleed Air from System
  • With the cap off, start the engine and let it run for several minutes.
  • Gently rock the bike side to side and blip the throttle to help any remaining air bubbles escape.
  • Watch for the coolant level to drop as air is released; add coolant as required.
8. Final Checks
  • Once the coolant remains steady at the base of the filler neck and all air is purged, reinstall the radiator cap.
  • Clean any spilled coolant from the bike.
  • Safely dispose of old coolant according to local environmental regulations.

2015 Husqvarna TC85 Model-Specific Notes

  • Coolant capacity: Approximately 0.95 liters (≈1 US quart) is typical for this model––always check the level after initial operation and bleed as needed.
  • Aluminum Radiators: Always use coolant designed for compatibility with aluminum materials to prevent corrosion and electrolysis.
  • Air Bleed Port: The 2015 TC85, like other KTM/Husqvarna 85cc models, may be equipped with a small bleeder screw on top of the cylinder head; using this port is essential for a complete air purge and reliable operation.
  • Track and Race Use: After extreme or muddy rides, inspect for debris caught in the radiators to avoid blockages and hot spots.

Proper coolant maintenance is vital for maximizing the performance and durability of your 2015 Husqvarna TC85. A fresh, correctly filled cooling system protects your engine even under the highest demands of racing and riding. 

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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.