How to Change the Coolant in a 2018 Sherco 300SE-R: A Step-By-Step Guide

Shop parts for a 2018 Sherco 300SE-R Dirt Bike.

If you own a 2018 Sherco 300SE-R, regular coolant changes are crucial for maintaining engine performance, preventing overheating, and maximizing the longevity of your high-performance dirt bike. Proper coolant maintenance is even more important for the Sherco's advanced liquid-cooled two-stroke powerplant, known for running hot under hard use and technical terrain. This model features a robust cooling system but does require attention to detail during service. Below you'll find a MotoSport proprietary guide tailored for your 2018 Sherco 300SE-R.

What You Need

  • Approved coolant (Minerva Perma Universal D 4 or equivalent, rated to at least -25°C)
  • Socket wrench set (M6 and M8)
  • Drain pan
  • Funnel
  • Replacement radiator bleed screw washer (recommended)
  • Clean rags
  • Torque wrench

Step 1: Prepare Your Bike

  • Ensure the bike is completely cool before starting–opening the radiator on a hot engine is dangerous.
  • Place the bike vertically on stable, level ground.
  • Remove the seat and side radiator panels for easier access if needed.

Step 2: Drain the Old Coolant

  • Position a drain pan beneath the water pump area.
  • Locate the coolant drain screw on the water pump and loosen it. Also, unscrew the radiator cap for better flow.
  • Allow all coolant to drain completely. Be patient so the system empties fully.
  • Dispose of the old coolant responsibly–never pour it down drains or on the ground.

Step 3: Bleed the System (Critical for Sherco Models)

  • On your 300SE-R, locate the radiator bleed screw (usually M6) on the left side of the radiator.
  • Remove this bleed screw. If possible, replace the washer for a perfect seal.

Step 4: Add New Coolant

  • Slowly pour approved coolant into the radiator filler neck, allowing it to fill until you see fluid begin to emerge from the open bleed screw. This purges air from the system.
  • Once a steady flow (no bubbles) comes out of the bleed screw, reinstall and torque the screw to 8Nm.
  • Continue filling at the radiator cap neck until the level is just below the rim (approximately 1.1 liters). Do not overfill.

Step 5: Check Levels in the Expansion Reservoir

  • Ensure the fluid in the reservoir reaches the "LEVEL" line when the bike is upright.
  • If needed, top up via the reservoir fill neck.

Step 6: Reassemble and Heat Cycle

  • Replace the radiator cap and all removed bodywork.
  • Start the engine and let it idle, monitoring for leaks. As the thermostat opens, the level may drop.
  • Once fully heat-cycled, allow the bike to cool and check coolant levels at both the radiator and reservoir, topping up if needed.

Important Tips for 2018 Sherco 300SE-R Owners

  • Always use a factory-approved coolant; water or other types can damage your engine and cooling system.
  • After every coolant change, double-check for leaks at drain and bleed screws.
  • If you notice persistent loss of coolant or see coolant leaking from the water pump weep hole, you may have a worn seal that needs replacing.
  • The Sherco's high temps mean changing coolant annually (or after every hard race season) is wise for best performance.

Caring for your 2018 Sherco 300SE-R with regular coolant changes ensures smooth runs and years of reliable, spirited riding. If you need OEM or performance parts for this bike, MotoSport has you covered.

Related Shopping Categories

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Shop Temperature Sensors for a 2018 Sherco 300SE-R Dirt Bike.

Shop Tools for a 2018 Sherco 300SE-R Dirt Bike.

Shop Radiator Hoses for a 2018 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.