How to Change the Coolant in a 2021 Husqvarna TX300i: MotoSport Guide
Shop parts for a 2021 Husqvarna TX300i Dirt Bike.
Keeping your 2021 Husqvarna TX300i’s cooling system serviced is crucial for powering through singletrack, racing at the limit, or surviving brutal summer heat. This proprietary MotoSport guide delivers step-by-step instructions tailored to your bike—with essential notes specific to the fuel-injected TX300i.
What You’ll Need
- Fresh, high-quality coolant compatible with aluminum radiators and two-stroke engines (avoid mixing different coolant types)
- Dirt bike stand
- 10mm socket and wrench
- Drain pan
- Clean funnel
- Shop towels
- Proper torque wrench (optional, recommended for reinstallation)
- Gloves and eye protection
2021 Husqvarna TX300i: Model-Specific Details
- Factory recommends using a non-silicate, phosphate-free coolant for optimal performance and corrosion protection.
- The coolant drain bolt is found on the right side of the cylinder, above the power valve cover.
- As a fuel-injected two-stroke with advanced engine temp sensors, it’s critical to fully remove trapped air from the cooling system to avoid false sensor readings and potential overheating.
Step-by-Step Coolant Change Procedure
-
Let the bike cool completely.
Never work on a hot cooling system–wait until the engine and radiators are cool to the touch to prevent burns. -
Elevate the dirt bike.
Stabilize the TX300i on a stand so it remains upright and level. -
Remove the radiator cap.
Locate the left radiator cap. Slowly twist it off to relieve any residual pressure. This step allows coolant to drain quickly and completely. -
Locate the coolant drain bolt.
The drain bolt is on the right cylinder, just above the power valve cover. Place a drain pan directly underneath, and use a 10mm socket to unscrew the bolt. Allow coolant to fully drain from both radiators. -
Optional: Flush the system.
If the old coolant looks dirty, pour distilled water through the radiator neck until the outflow runs clear. Reinstall the drain bolt before refilling with coolant. -
Inspect the drain bolt washer.
Check the sealing washer or O-ring on the drain bolt before reinstalling. Replace if worn or damaged to prevent leaks. -
Refit and torque the drain bolt.
Hand-tighten securely. For best results, use a torque wrench and follow the factory specification (consult your owner manual). -
Refill with new coolant.
Slowly pour coolant into the radiator using a clean funnel. Fill to the base of the neck but do not overfill. -
Bleed trapped air.
The TX300i is susceptible to air pockets. Gently rock the bike side-to-side, then squeeze the hoses to help air escape. If accessible, use the cylinder head bleeder screw by loosening it until coolant flows steadily, then retighten. -
Reinstall the radiator cap.
Ensure it’s clean and seats fully. -
Start & heat cycle the engine.
Let the bike idle until it starts to warm up and circulate coolant. Allow to cool fully, then re-check and top off the radiator and reservoir as needed. -
Double-check for leaks.
Inspect around the drain bolt and radiator for any fluid seepage.
Additional Notes for TX300i Owners
- Always dispose of old coolant responsibly—never pour it down drains or onto the ground.
- This model uses a pressurized cooling system–never open the radiator cap while hot.
- Check coolant level before every ride, especially after a coolant service.
- If you see persistent bubbling, foaming, or loss of coolant, check for leaks or improper bleeding of air.
Regular cooling system maintenance helps your TX300i stay cool and reliable on track or trail–trust MotoSport for all your OEM parts, fluids, and essentials specific to your Husqvarna.
Related Shopping Categories
Shop Radiators for a 2021 Husqvarna TX300i Dirt Bike.
Shop Coolant for a 2021 Husqvarna TX300i Dirt Bike.
Shop Temperature Sensors for a 2021 Husqvarna TX300i Dirt Bike.
Shop Tools for a 2021 Husqvarna TX300i Dirt Bike.
Shop Radiator Hoses for a 2021 Husqvarna TX300i 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.