How to Change the Coolant in a 2020 Sherco 300SE-R

Shop parts for a 2020 Sherco 300SE-R Dirt Bike.

Regular coolant changes are essential for keeping your 2020 Sherco 300SE-R running strong. The SE-R’s high-performance two-stroke engine relies on proper cooling, and neglecting coolant maintenance can lead to overheating, corrosion, or even engine failure. Fortunately, changing the coolant on this model is straightforward when armed with the right tools and steps.

What You Need Before Starting

  • Fresh, approved coolant (Minerva Perma Universal D 4 or equivalent, rated -25°C minimum freeze point)
  • Drain pan
  • Basic hand tools: screwdriver, 8 mm and 10 mm sockets
  • Replacement radiator cap or bleed screw gasket (if needed)
  • Gloves and safety glasses

Preparation

  • Ensure the bike is completely cool – hot coolant is dangerous and under pressure.
  • Set the Sherco 300SE-R upright on a flat, stable surface.
  • Remove the skid plate, radiator shrouds, and seat if access is limited.

Draining the Coolant

  • Position your drain pan under the right side of the engine.
  • Locate the radiator cap at the top of the left radiator, and unscrew it.
  • Find the coolant drain bolt (often on the lower engine case, typically 8 mm). Remove it and allow all coolant to drain out completely.
  • To speed up draining, loosen (or remove) the radiator bleed screw located on the left side of the radiator. This will help eliminate trapped fluid and air.
  • Properly dispose of drained coolant at an approved collection center to protect the environment.

Refilling the Coolant

  • Reinstall and torque the drain bolt to factory spec (6Nm). Replace the gasket if needed.
  • With the bleed screw still open, fill the radiator with fresh coolant until it flows steadily (no bubbles) from the bleed screw opening.
  • Install the bleed screw with a new gasket and torque to 8Nm.
  • Continue topping off the radiator until coolant reaches the base of the filler neck (approximately 1.1 liters for this model).
  • Install the radiator cap securely.

Checking for Air and Final Steps

  • Start the engine and let it idle. Watch the temperature and inspect for any leaks.
  • Let the engine run until it's fully warmed up (the radiator fan activates or the frame feels warm). Shut off the engine and allow it to cool completely.
  • Check the coolant level in the radiator and reservoir again. Top off if necessary.
  • Repeat the heat cycle and level check if bubbles were seen or coolant dropped after the first cycle.

Model-Specific Considerations for the Sherco 300SE-R

  • The 300SE-R uses a closed pressurized system with a bleed screw specifically for precise deaeration.
  • Do not substitute water or automotive coolant–use only compatible motorcycle coolant rated safe for aluminum components.
  • Inspect hoses, radiator, and water pump area for leaks and signs of wear while you have access. Pay attention to the water pump weep hole (directly below the water pump)–a persistent leak there may indicate a failed seal and need for professional service.
  • The engine holds about 1.1 liters of coolant. Overfilling can cause overflow from the expansion tank and should be avoided.

When to Change Your Coolant

  • Sherco recommends coolant changes every 2 years or 60 hours of use, whichever comes first, but more frequent changes may be needed for severe riding or muddy conditions.

For all your maintenance needs and genuine replacement parts, shop parts for a 2020 Sherco 300SE-R Dirt Bike.

Related Shopping Categories

Shop Radiators for a 2020 Sherco 300SE-R Dirt Bike.

Shop Coolant for a 2020 Sherco 300SE-R Dirt Bike.

Shop Temperature Sensors for a 2020 Sherco 300SE-R Dirt Bike.

Shop Tools for a 2020 Sherco 300SE-R Dirt Bike.

Shop Radiator Hoses for a 2020 Sherco 300SE-R 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.