How to Change the Coolant in a 2018 Honda CRF125FB

Shop parts for a 2018 Honda CRF125FB Dirt Bike.

Keeping your 2018 Honda CRF125FB's cooling system in top shape is crucial for peak performance, engine longevity, and worry-free rides. A regular coolant change ensures proper heat dissipation and protects against freeze damage and corrosion. This guideexclusive to MotoSportdetails every step to change your CRF125FB's coolant safely and efficiently, along with important notes specific to this model.

What You'll Need

  • Silicate-free coolant formulated for aluminum engines (pre-mixed or mix with distilled water).
  • Drain pan.
  • Socket set and ratchet (primarily 8mm, 10mm, and 12mm sizes).
  • Phillips screwdriver.
  • Funnel.
  • Shop rags or paper towels.
  • Protective gloves and eyewear.

Preparation

  • Ensure the engine is cool to avoid burns.
  • Set the CRF125FB securely on a stand or level surface to prevent tipping.
  • Clean any dirt around the radiator cap and drain bolt area for a debris-free environment.

Step-by-Step Coolant Change Process

  1. Remove the Left Side Cover
    - Using your socket set, remove the bolts securing the left side cover. Gently pull the cover outthis provides access to the radiator and coolant reservoir. Always note the bolt and grommet placement for hassle-free reinstallation.
  2. Access and Open the Radiator Cap
    - Using a cloth, slowly remove the radiator cap to release any residual pressure. This allows the old coolant to drain completely.
  3. Locate and Remove the Drain Bolt
    - Position your drain pan under the water pump or lowest cooling system bolt (typically on the right lower side of the engine case). Remove the coolant drain bolt with an appropriate socket and allow the coolant to drain fully. If your model has a dedicated coolant drain bolt, check for a sealing washer and replace it if damaged.
  4. Flush the Cooling System (Recommended)
    - If the drained coolant is dirty or you're switching coolant types, flush the system with distilled water. Reinstall the drain plug temporarily, fill with distilled water, run the engine briefly, then drain again.
  5. Reinstall the Drain Bolt
    - Inspect the drain plug washer for wear or damage and replace if necessary. Torque the drain bolt to manufacturer specs (do not overtighten).
  6. Add New Coolant
    - Using a funnel, slowly pour coolant into the radiator until full. Avoid overfilling the reservoir, which can cause overflow or pressure issues.
  7. Bleed Air From the System
    - With the radiator cap off, start the engine and let it idle for a few minutes. Gently rock the bike side to side to help air bubbles escape. Monitor coolant leveladd more if the level drops. Do not let the engine overheat during this process.
  8. Reinstall the Radiator Cap and Side Cover
    - Once the coolant remains level and no more air bubbles appear, install the radiator cap securely. Reattach the left side cover by aligning tabs, prongs, and bolts in their original positions.
  9. Final Checks
    - After a test ride, double-check coolant levels and inspect for any leaks near the drain plug or radiator. Top off if necessary.

Model-Specific Notes for the 2018 CRF125FB

  • The CRF125FB's cooling system is compact and efficient, but improper coolant type can cause premature corrosion. Always use a silicate-free blend for aluminum engines.
  • The plastic radiator and reservoir components are durable but avoid using tools that could crack or score surfaces during removal. Hand-tighten plastics and avoid over-torquing bolts.
  • Replacing the drain bolt's crush washer when changing coolant is recommended to prevent slow leaks over time.

When to Change Your Coolant

  • Honda recommends coolant changes every two years or as indicated in your owner's manual, whichever comes first. Harsh riding conditions or long storage may warrant more frequent changes.
  • Discoloration, debris, or oil mixing with coolant signals a need for immediate service.

Why Change Your Coolant?

  • Ensures optimal engine operating temperature and prevents overheating.
  • Protects internal engine components from corrosion, scaling, and freeze damage.
  • Maintains consistent, safe riding performance in all conditions.

With this MotoSport-specific guide, you can confidently change the coolant in your 2018 Honda CRF125FB and keep your bike's cooling system ready for every adventure.

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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.