How to Change the Coolant in a 2023 Suzuki DRZ400S

Shop parts for a 2023 Suzuki DRZ400S Dirt Bike.

Routine coolant maintenance on your 2023 Suzuki DRZ400S is essential for preserving performance and reliability on and off the trail. The DRZ400S uses a liquid-cooled engine, which demands periodic flushing and replacement of coolant to prevent overheating, corrosion, and premature wear.

What Makes the 2023 DRZ400S Cooling System Unique?

  • The DRZ400S lacks a thermostat and often does not have a water neck bleeder screw, depending on the radiator design and year.
  • Like other DRZ400 models, the left radiator typically has an air bleed screw for proper air evacuation.
  • Plastic side covers can come off easily–be careful when removing them to avoid damage or loss.

Tools & Supplies Needed

  • Socket set (at minimum, 12mm to access drain bolts)
  • Medium and small Phillips screwdrivers
  • Pre-mixed 50/50 motorcycle-safe coolant (avoid using automotive antifreeze with silicates or phosphate)
  • Catch pan
  • Funnel
  • Shop rags
  • Optional: Distilled water for flushing if contamination is suspected

Step-by-Step Coolant Change Guide

  1. Prepare the Bike:
    • Ensure the engine is cool to avoid burns and pressure spray.
    • Remove the left plastic side cover using a 12mm socket to access the water pump and drain bolt.
  2. Drain the Old Coolant:
    • Remove the radiator cap from the left radiator to allow air entry and faster draining.
    • Locate and remove the water pump drain bolt (usually found at the bottom of the water pump cover). Allow all coolant to drain into your catch pan.
  3. Flush the System (Optional):
    • If switching coolant types or if the old coolant was dirty, flush the system with distilled water.
    • Replace the drain bolt temporarily, fill the radiator with distilled water, run the engine briefly, turn off, cool, and then drain again.
  4. Install the Drain Bolt:
    • Inspect the drain bolt washer for wear–replace if necessary.
    • Reinstall the bolt securely (do not overtighten).
  5. Fill with New Coolant:
    • Pour coolant into the right radiator using a funnel.
    • If your model has an air bleed screw on the left radiator, open it a few turns. As you fill, allow air to escape through the screw until you see coolant, then snug the screw closed.
    • Lean the bike to the left and right to help air reach the radiator neck, then top up again as needed.
  6. Bleed Air from the System:
    • Start the engine with the radiator cap off. Let it idle and come up to temperature but do not leave it unattended. Watch for air bubbles escaping; top off with coolant as the level drops.
    • Once the engine reaches operating temperature, shut it off and let it cool completely.
    • Check and top off the radiator again. Add about 1 inch of coolant to the reservoir bottle.
  7. Complete and Reassemble:
    • Replace the radiator cap.
    • Reinstall the plastic side cover.
    • Dispose of old coolant safely and responsibly according to local regulations.

Key Reminders for Your DRZ400S:

  • Do not overfill the radiator or overflow bottle–leave room for expansion.
  • If you ride in harsh conditions, inspect your radiator fins and hoses for damage when you service coolant.
  • Avoid using coolant with silicates/phosphates, which can be abrasive to the water pump and internal seals.
  • Always double-check air bleeding–trapped air leads to overheating, a common pitfall with this model.

Following these steps will ensure your DRZ400S's cooling system remains in peak condition, helping you avoid overheating on the trail and maximizing engine life for every ride.

Related Shopping Categories

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Shop Tools for a 2023 Suzuki DRZ400S Dirt Bike.

Shop Radiator Hoses for a 2023 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.