How to Change the Coolant in a 2012 Kawasaki KX85

Shop parts for a 2012 Kawasaki KX85 Dirt Bike.

Maintaining your 2012 Kawasaki KX85 is crucial for performance and long-term engine health—and changing the coolant is an essential part of routine service. The KX85 is known for its high-revving two-stroke engine, excellent for youth racing, but proper cooling is critical due to its compact liquid-cooling system. Follow this proprietary step-by-step MotoSport guide for a robust, clean coolant change specific to your KX85.

Tools & Supplies Needed

  • New coolant (check owner's manual for recommended type—avoid mixing coolant types)
  • Ratchet and size 8mm or 10mm socket for drain bolt
  • Funnel
  • Catch pan
  • Distilled water for flushing
  • Compressed air source (optional for extra flush)
  • New crush washer for drain bolt (recommended)
  • Safety gloves

Step-by-Step Coolant Change Process

  • Allow the Engine to Cool – Never open the radiator cap on a hot engine. Let your KX85 sit and cool fully before starting.
  • Remove the Radiator Cap – Twist off the radiator cap to relieve internal pressure and prepare for draining.
  • Locate the Coolant Drain Bolt – On the KX85, the drain bolt can be found on the side of the cylinder near the water pump area. Place your catch pan underneath to prevent spills.
  • Loosen & Remove the Drain Bolt – Use the correct socket to carefully loosen the drain bolt. Allow the coolant to flow completely into your catch pan. The OEM drain bolt may have a crush washer—inspect for damage and replace if needed for a proper seal.
  • Flush the Cooling System – If switching coolant types or for extra cleaning, flush with distilled water. Replace the drain bolt, pour distilled water into the radiator, run the engine briefly, and drain again. For thorough flushing, you may also detach radiator hoses and use compressed air to clear out stubborn residue.
  • Reinstall the Drain Bolt (Use a New Washer) – Clean the sealing surfaces and install a new crush washer for leak prevention. Re-tighten to manufacturer specification.
  • Fill with Fresh Coolant – Using a funnel, pour new coolant into the radiator until full. Tilt the bike side to side to aid air removal, then top off as needed.
  • Bleed the Cooling System – Start the bike and let it idle with the cap off for several minutes, watching for air bubbles escaping. Add coolant to maintain correct level.
  • Replace Radiator Cap & Inspect – Secure the radiator cap, clean up any spills, and check for leaks at all hose connections and drain bolt.

Important KX85-Specific Notes

  • Replace Crush Washers Every Service – The KX85 coolant drain bolt has a crush washer. For optimal seal, always use a new washer at each change.
  • Flush More Often When Changing Coolant Types – If moving from a water-based to a non-water-based coolant, thorough flushing is vital to prevent mixing and overheating issues.
  • Disposal Matters – Always dispose of old coolant responsibly. It is toxic—never pour down drains or onto soil.
  • Inspect Hoses and Radiator – Check for bulging, cracks, or leaks. This age of KX85 can develop hose or radiator deficiencies if not regularly inspected. Replace any worn components while you have the system open.
  • Use Only Distilled Water for Flushing – Tap water can contaminate the system with minerals, causing scale buildup and overheating. Always flush with distilled water only.

Routine coolant changes boost longevity and prevent race-day breakdowns. For more KX85 parts and maintenance essentials, shop parts for a 2012 Kawasaki KX85 Dirt Bike.

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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.