How to Change the Coolant in a 2016 Suzuki DRZ400S

Shop parts for a 2016 Suzuki DRZ400S Dirt Bike.

Keeping your 2016 Suzuki DRZ400S running cool is crucial for both performance and engine longevity. Coolant maintenance is often overlooked, but changing it regularly helps prevent overheating and corrosion inside the engine. The DRZ400S uses a liquid cooling system that is both robust and requires periodic attention. Here–s how to handle coolant replacement at home, with model-specific tips for your MMY (Make, Model, Year) dirt bike.

What You–ll Need:

  • Pre-mixed 50/50 motorcycle coolant (avoid coolant with silicates that can damage seals)
  • Socket set (12mm for side covers, 10mm for drain bolt)
  • Medium Philips screwdriver
  • Drain pan
  • Shop towels/rags
  • Funnel

Step-by-Step Guide

1. Preparation

  • Ensure the engine is completely cool before starting to avoid burns.
  • Position your DRZ400S on a level surface or stand.

2. Remove the Side Cover

  • Use the 12mm socket to remove the left side plastic panel. This grants access to the water pump and the coolant drain bolt.

3. Drain Old Coolant

  • Place the drain pan beneath the water pump.
  • Loosen the small screw that secures the radiator cap, then remove the cap to relieve pressure and allow air into the system for better draining.
  • Using a 10mm socket, remove the coolant drain bolt from the water pump cover and let all coolant run out. Open the radiator cap and the expansion tank cap if equipped, to facilitate full evacuation.

4. Inspect the System

  • Check for any sludge or debris in the drained coolant. If switching coolant types (especially from water-based to non-water-based), flush the system by blowing compressed air through the hoses for thorough cleaning.
  • Inspect visible hoses & clamps for cracks, bulges, or corrosion—replace if needed.

5. Replace or Reinstall the Drain Bolt

  • Install the drain bolt and torque it to manufacturer specifications. Do not overtighten, as this may damage the threads.

6. Refill Coolant System

  • Slowly pour the pre-mixed coolant into the right radiator neck using a funnel.
  • The 2016 DRZ400S has a unique air-bleed screw on top of the left radiator and often another at the water neck (top front of cylinder head). Open both a few turns while filling; close each after coolant seeps out and no more air bubbles appear. If your water neck points straight up, there may not be a bleeder screw—skip that step if not present.
  • Fill until the radiator is topped off. Lean the bike left and right to help trapped air escape, then top off again as necessary.

7. Replace Caps & Start Engine

  • With the radiator and any bleeder screws tightly secured, replace the radiator cap.
  • Start the engine and allow it to idle until it reaches operating temperature (just a few minutes). Observe the coolant level—if it drops, shut off the engine and cautiously top off when cool again.

8. Repeat Burping if Necessary

  • Repeat the fill-and-burp process to ensure all air is purged. The DRZ400S coolant system holds about 1.3 qt (1.2 L), not including the expansion tank. Finish by adding coolant to the overflow reservoir (about 1 inch of fluid).

9. Final Checks & Clean-Up

  • Inspect for leaks around drain plug, hoses, and cap.
  • Reinstall side panel. Dispose of old coolant responsibly.

Model-Specific Notes for the 2016 DRZ400S

  • This bike–s cooling system is designed for off-road challenges, but the radiator cores can be prone to damage in tip-overs. Inspect both radiators for bent fins or leaks while servicing the coolant.
  • Some DRZ400S units – depending on region & build date – may lack the water neck bleeder screw. If so, rely on slow filling, careful burping, and tipping the bike side-to-side to remove air effectively.
  • Only use recommended, motorcycle-specific coolant to avoid gasket deterioration and corrosion inside the magnesium engine covers.
  • Plan on a coolant change every two years, or sooner if you ride aggressively in hot or muddy conditions.

Proactive coolant maintenance preserves both the ride and value of your DRZ400S. Following these steps gives you confidence and consistency, whether on the trail, dual sport routes, or daily commutes.

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Shop Radiator Hoses for a 2016 Suzuki DRZ400S Dirt Bike.

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.