How to change the coolant in a 2001 Suzuki DRZ400S Dirt Bike

How to Change the Coolant in a 2001 Suzuki DRZ400S

Shop parts for a 2001 Suzuki DRZ400S Dirt Bike.

Keeping your 2001 Suzuki DRZ400S running cool is essential, whether you are hitting singletrack, fire roads, or your local trails. Over time, coolant degrades and loses its ability to protect your engine from overheating and corrosion. Here is the step-by-step MotoSport.com guide to changing your coolant on the DRZ400S, including DRZ-specific tips for this legendary dual sport.

What You Need

• 50/50 premixed coolant designed for aluminum radiators (do not use pure water or incompatible coolants)
• Distilled water (optional, for flushing)
• Socket set (10 mm and 12 mm)
• Small Phillips screwdriver
• Drain pan
• Shop towels
• Safety goggles and gloves

Step-by-Step Coolant Change

1. Preparation:
   • Allow the engine to cool completely before starting. Never open the radiator cap on a hot engine.
   • Remove your left side panel to access the radiator and water pump drain bolt area.
2. Draining Old Coolant:
   • Remove the radiator cap (held by a small screw). This releases pressure and allows coolant to flow freely.
   • Locate the coolant drain bolt on the water pump cover (10 mm head). Place a drain pan underneath and carefully remove the bolt to let the coolant drain.
   • If desired, flush the system by pouring distilled water through the radiator cap opening and letting it drain until clear. Do not leave plain water in the system after flushing.
3. Inspect & Replace If Needed:
   • Inspect hoses for cracks or damage. Replace them if needed to prevent leaks.
   • Ensure the sealing washer is in good shape before reinstalling the drain bolt. Snug the bolt gently; overtightening can crack the cover.
4. Refilling With Coolant:
   • Some 2001 DRZ400S models may have a bleeder screw at the top front of the cylinder head (water neck). Loosen this screw a few turns for air to escape as you fill the system. If your model lacks this feature, skip to the next step.
   • There is also an air bleed screw on the top of the left radiator. Loosen this as well.
   • Slowly pour 50/50 coolant into the right radiator until it reaches the inlet. Watch for coolant to begin seeping from the bleeder screws; once it does, snug them back down to the correct torque: 6.0 N·m (0.6 kgf-m, 4.3 lb-ft).
5. Finishing Up:
   • Tighten the radiator cap securely.
   • Start the engine and let it idle until warm. This purges remaining air. Allow the engine to cool, then recheck and top off coolant if necessary.
   • Proper capacity is approximately 1.25 L (1.3 US qt).

DRZ400S Coolant Maintenance Notes

• Coolant Type: Always use a coolant safe for aluminum radiators and blended with distilled water in the 50:50 to 40:60 ratio. Avoid silicate-heavy or generic automotive coolants, which can damage the system.
• Check and Replace Regularly: Suzuki recommends inspecting coolant levels and hoses every 30 hours of operation, and after hard use in mud or sand. Replace coolant every 2 years or sooner under harsh conditions.
• Watch for Leaks: The DRZ's cooling system is robust, but leaks at hose clamps or the water pump seal can develop with age. Check after rides, especially if you notice drops in coolant level or overheating.
• Model Peculiarities: Some 2001 DRZ400S bikes may lack certain air bleeder screws. If your cylinder head water neck points straight up, it may not have a bleeder or a thermostat—confirm before you begin.

Regular coolant changes are simple insurance for your DRZ's reliability and longevity. The legendary 400S is tough, but preventative maintenance makes all the difference for riders who expect performance season after season. Ride ready — and ride cool — with these MotoSport.com tips and parts on hand for every coolant change.

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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.