How to Change the Coolant in a 2021 Sherco 300SE-R: MotoSport Guide
Shop parts for a 2021 Sherco 300SE-R Dirt Bike.
Keeping your 2021 Sherco 300SE-R performing at its best requires regular cooling system maintenance. Coolant should be changed periodically to prevent overheating, engine damage, and ensure smooth operation. Sherco's 300SE-R uses a liquid cooling system designed for harsh riding conditions, but following precise procedures is crucial to maintain reliability and longevity.
Tools & Supplies Needed
- Approved motorcycle coolant (Sherco recommends Minerva Perma Universal D 4 –25°C or equivalent)
- Drain pan
- Socket set (notably 8mm and 10mm for bolts and drain screws)
- New radiator bleed screw gasket if necessary
- Small funnel
- Clean rags
- Torque wrench (for proper reassembly)
Step-by-Step Coolant Change Instructions
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Preparation
- Ensure the bike is cold before starting. Hot coolant can cause burns.
- Place the 300SE-R on a stable, level surface, using a stand if possible.
- Remove the radiator cap carefully to release residual pressure – do this slowly.
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Drain Old Coolant
- Place a drain pan beneath the engine under the right side water pump area.
- Locate and remove the coolant drain screw (often an 8mm bolt near the water pump area). Allow all coolant to fully drain.
- Optionally, remove the lower radiator hose for a more complete drain.
- Dispose of old coolant properly at a certified collection center – do not pour into drains or onto the ground.
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Flush Cooling System (Optional but Recommended)
- Refill with distilled water, run the engine briefly (no more than a minute), shut off, let cool, and repeat the drain steps. This helps remove residual contaminants.
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Refill with Fresh Coolant
- Tighten the drain screw to 6Nm (hand tight plus a small turn if no torque wrench is available).
- Remove the bleed screw located on the left side of the radiator. This helps air escape as you fill.
- Slowly pour new coolant into the radiator until fluid flows consistently from the bleed screw without air bubbles.
- Reinstall and tighten the bleed screw with a new gasket if necessary (8Nm torque recommended).
- Continue filling the radiator until the coolant reaches the "LEVEL" mark, usually about 1.1 liters.
- Install and tighten the radiator cap.
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Check for Leaks & Final Steps
- Start the bike and let it idle for a few minutes, monitoring for leaks.
- After cooling, recheck coolant level and top off if needed. Confirm fluid level at the reservoir matches the "LEVEL" mark.
Special Notes for 2021 Sherco 300SE-R Owners
- Use only recommended coolants; alternative fluids or water alone can compromise corrosion protection and potentially damage your engine and seals.
- The 300SE-R has a bleed screw for reliable air removal from the cooling system, which is a key step to avoid air pockets and possible engine overheating.
- When reinstalling screws and parts, always use manufacturer torque specs to prevent stripping threads or overtightening.
- If you notice recurring fluid loss or coolant at the weep hole near the water pump, this could indicate a water pump seal failure, a known potential issue on these models. In this case, additional service may be required.
When to Change Your Coolant
- Follow the maintenance schedule in your owner's manual for periodic coolant replacementtypically every twelve months, or whenever coolant appears dirty or degraded.
- Replace coolant after any major engine work that involves opening the cooling system.
Ride Confident: Keep Your 300SE-R Ready for the Next Adventure
Changing your Sherco's coolant as described ensures dependable operation and full engine protection during demanding rides. For genuine parts, tools, and high-performance upgrades specifically for your 2021 Sherco 300SE-R, head to MotoSport for everything you need.
Related Shopping Categories
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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.