How to Change the Coolant in a 2023 GAS GAS EX 300

Shop parts for your ride now!

Keeping your 2023 GAS GAS EX 300 running at peak performance means proper maintenance of all major systems, including the cooling system. Changing your coolant regularly helps prevent overheating, corrosion, and internal engine damage. Below is a MotoSport proprietary step-by-step guide tailored for your EX 300 to ensure a smooth coolant change.

What You Will Need

  • Fresh, motorcycle-specific coolant (check for aluminum-friendly, silicate-free formulas)
  • Catch pan for old coolant
  • Socket set and flathead screwdriver
  • Clean rags for spills
  • Protective gloves and eyewear (coolant is hazardous)

Before You Start

  • Only service the cooling system when the bike is completely cool to avoid burns or pressurized coolant spray.
  • Work in a well-ventilated area and dispose of old coolant responsibly.

Step 1: Remove Necessary Bodywork

Depending on access, you may need to remove the front number plate and side shrouds to conveniently reach the radiator cap and drain.

Step 2: Locate the Radiator Cap and Drain Bolt

  • On the 2023 GAS GAS EX 300, the radiator cap is usually on the upper left radiator.
  • The coolant drain bolt is typically found on the lower water pump cover (right side of the engine). Refer to your owner's manual for exact placement.

Step 3: Drain the Old Coolant

  1. With the bike upright, place the catch pan under the water pump area.
  2. Slowly loosen and remove the radiator cap to release pressure.
  3. Remove the drain bolt from the water pump cover. Allow coolant to flow completely into the pan.
  4. Remove the bleed screw (if equipped, often located on top of the cylinder head or radiator) to help air move and fully drain the system.
  5. Inspect the old coolant for oil, debris, or rust, which can signal internal issues.

Step 4: Flushing the System (Recommended for Heavy Use or Mud)

  • After draining, reinstall the drain bolt and fill with distilled water.
  • Run the engine for a few minutes to circulate water.
  • Repeat the drain process to remove as much old coolant and contaminants as possible before refilling with new coolant.

Step 5: Refill With New Coolant

  1. Reinstall and torque the drain bolt as specified.
  2. Fill the cooling system through the radiator cap slowly, allowing coolant to fill both radiators.
  3. If present, open the cylinder head bleeder screw until coolant flows without bubbles, then close securely.
  4. Fill until just below the bottom of the filler neck. Do not overfill.

Step 6: Bleed and Recheck the System

  • Start the bike and let it idle with the radiator cap off for 1-2 minutes to help air escape.
  • Top off coolant if the level drops.
  • Replace and tighten the cap securely once no more air bubbles appear and the system is full.
  • After warming up, shut off the engine, allow it to cool, and check coolant level one final time. Top off as needed.

Important Model Notes: 2023 GAS GAS EX 300

  • This model uses a modern closed-loop, pressurized cooling system designed for high-performance enduro use.
  • Coolant capacity is roughly 1-1.1 liters – do not exceed the overflow line.
  • Always use coolant recommended for aluminum engine components to prevent corrosion.
  • Check for leaks at the water pump, radiators, and hoses after refill and after your first ride.

Safety and Maintenance Tips

  • Check coolant level and condition before every ride, especially in varying climates.
  • Change coolant at least once per year, or more frequently if you race or ride in muddy/extreme conditions.
  • Coolant is hazardous – wash away any skin contact immediately, and keep out of reach of children and animals.

Changing your coolant is a quick way to protect your GAS GAS EX 300’s engine and ensure reliable performance year-round. For a complete range of maintenance parts, visit MotoSport now and keep your ride dialed in.

Related Shopping Categories

Shop Radiators for Your Ride

Shop Coolant for Your Ride

Shop Temperature Sensors

Shop Tools

Shop Radiator Hoses for Your Ride

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.