How to Change the Coolant in a 2016 Kawasaki KX85

Shop parts for a 2016 Kawasaki KX85 Dirt Bike.

The 2016 Kawasaki KX85 is a top choice for aspiring motocross riders and performance-focused youth. Routine coolant changes will keep your bike running cool, prevent overheating, and extend the life of your engine and cooling system. The KX85 features dual radiators and a high-revving two-stroke engine, making reliable cooling essential for race days and long trail sessions. Here's a complete, proprietary MotoSport guide to replacing your coolant with confidence and care for your 2016 KX85.

Things You'll Need

  • Fresh pre-mixed motorcycle coolant (ensure it's compatible with aluminum radiators).
  • 10mm and 8mm socket or wrench.
  • Large drain pan to catch old coolant.
  • Funnels for controlled pouring.
  • Rags to wipe any spills.
  • Gloves – coolant is slippery and toxic.
  • Compressed air (recommended for full flush if changing coolant type).

Before You Begin

  • Only change coolant when the engine is completely cool – hot coolant can cause burns and high system pressure can spray fluid.
  • Work in a well-ventilated area and keep pets and kids away – used coolant is toxic.

Step 1: Drain the Old Coolant

  1. Remove the radiator shrouds using your 8mm wrench if needed for better access.
  2. Locate the radiator cap at the top of the left side radiator. Do not open it yet.
  3. Place the drain pan below the water pump cover (right side near the bottom of the engine).
  4. Loosen, then remove the 10mm coolant drain bolt located at the bottom of the water pump cover. Some KX85 models have a small copper washer here – ensure you don't lose it.
  5. Open the radiator cap slowly now to allow the system to vent and drain completely.
  6. Gently tilt the bike side to side to ensure all coolant drains.

Optional: Flush the Cooling System

  • If switching coolants or if the old coolant is dirty, flush the system with distilled water.
  • Replace the drain bolt, fill radiator with distilled water, run the bike for a few minutes, let it cool, and drain again.
  • For a full flush, remove the lower radiator hose and use compressed air carefully to blow out any remaining fluid from the system.

Step 2: Refit – Prepare for Filling

  1. Inspect the drain bolt and copper washer; replace if damaged.
  2. Reinstall and gently torque the coolant drain bolt. Do not overtighten – hand snug is usually sufficient.

Step 3: Fill with New Coolant

  1. Using a funnel, slowly fill the radiator with the recommended pre-mixed coolant to the base of the filler neck.
  2. Tap the radiator hoses gently by hand to help any trapped air bubbles rise and escape.
  3. Squeeze the main radiator hose a few times, then top off with coolant if the level drops.

Step 4: Bleed – Remove Air

  • With the radiator cap off, briefly start the bike and let it idle for 30-60 seconds, watching for coolant movement (do not rev or let it overheat).
  • Watch for bubbles – this means trapped air is escaping. Shut off engine, let sit, and top off if needed.
  • Securely reinstall the radiator cap, ensuring it clicks into the locked position. Do not overfill – overfilling reduces efficiency.

Step 5: Final Checks

  • Clean any coolant drips, refit shrouds, and start the engine. Check for leaks as it comes to temperature.
  • After your first ride, re-check coolant level – top off if necessary as air may continue to work its way out.

Important Notes for 2016 KX85 Owners

  • The 2016 KX85 uses dual aluminum radiators which are high efficiency but can clog if old or contaminated coolant is left in the system.
  • Never use regular automotive coolant designed for older vehicles with copper or brass systems – always use a coolant specifically labeled as safe for motorcycles with aluminum components.
  • Coolant should be inspected every 20 hours of use, and replaced at least once per season – more often if you ride in hot, sandy, or muddy conditions.

Disposal – Be Responsible

  • Do not pour used coolant down the drain or on the ground. Collect all old coolant in a sealed container and take it to a recycling center or auto parts store that accepts waste fluids.

Keep your KX85 running like a champion by making coolant changes part of your routine maintenance – and rely on MotoSport for all parts, upgrades, and support.

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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.