How to Change the Coolant in a 2016 Suzuki DRZ400SM

Shop parts for a 2016 Suzuki DRZ400SM Dirt Bike.

Keeping your DRZ400SM running cool is vital, especially if you push it on spirited street rides or tackle technical trails. Routine coolant changes ensure the engine is protected from overheating, corrosion, and premature wear. The 2016 Suzuki DRZ400SM has a simple cooling system, but paying attention to the purge process and using the right coolant are key. Here is our MotoSport guide to changing coolant in this reliable thumper.

Tools & Supplies Needed

  • Pre-mixed 50/50 motorcycle coolant (silicate-free, phosphate-free, aluminum-compatible)
  • 12 mm socket and ratchet
  • Phillips screwdriver
  • Small drain pan
  • Rags for cleanup
  • Protective gloves

Step-by-Step: Draining Old Coolant

  • Let the engine cool completely before you begin to avoid burns.
  • Remove the seat and left side panel, if equipped, to access the radiator cap and water pump cover.
  • Place a drain pan under the water pump area (right side of the engine).
  • Remove the radiator cap for easier draining–there may be a small securing screw.
  • Use your 12 mm socket to remove the water pump drain bolt at the bottom of the water pump cover. Let all fluid drain.
  • If equipped with a radiator overflow bottle, remove and drain it as well.

Refilling the Cooling System Properly

  • Reinstall the water pump drain bolt and torque it snug. Do not overtighten.
  • If your DRZ400SM has air bleed screws on the top front of the cylinder head (water neck) and on the left radiator, open both a few turns to help purge trapped air. Not every DRZ comes with both bleed screws, so check your model–if you have neither, skip to the next step.
  • Slowly fill the right radiator (the filler neck side) with new coolant. As you pour, you may see air bleeding out the open bleed screws; as soon as coolant dribbles steadily from a bleed screw, snug it closed. Repeat for the other bleed screw, if present.
  • Continue filling until the radiator neck is full. Gently rock the bike from side to side to encourage air bubbles to escape, topping off as necessary.
  • Replace the radiator cap.
  • Fill the coolant overflow bottle to the "Full" mark with about one inch of coolant if drained earlier.

Final Checks & Tips for the DRZ400SM

  • Start the engine and let it idle for a few minutes to reach operating temperature, monitoring the temperature and watching for leaks.
  • Shut off the bike, let it cool, and carefully remove the radiator cap. Top off coolant again if the level has dropped as trapped air escapes.
  • If you regularly ride in hot climates or traffic, monitoring the cooling fan (if installed) and considering a coolant upgrade can offer extra protection.
  • The DRZ400SM does not have a thermostat in the cooling system. Therefore, warm-up time and cold weather running differ from many street bikes–always let it idle a bit after a coolant change to purge all air before hard riding.
  • Check all hose clamps and connections for leaks after a test ride.

Important Model-Specific Notes

  • The 2016 DRZ400SM's single-cylinder, liquid-cooled engine is durable but sensitive to air bubbles in the cooling system. Proper bleeding is crucial to prevent overheating.
  • Factory coolants are typically blue or green; do not mix colors or types, and always use a motorcycle-approved formula.

Proper coolant service on your DRZ400SM will extend the life of vital components and keep your bike running at its best the next time you hit the road or your favorite twisty shortcut.

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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.