How to Change the Coolant in a 2015 Honda CRF125FB: MotoSport Guide
Shop parts for a 2015 Honda CRF125FB Dirt Bike.
Changing the coolant in your 2015 Honda CRF125FB is a fundamental maintenance task that keeps your engine running cool and extends the life of critical components. The CRF125FB uses a compact liquid-cooled engine, so proper coolant change intervals are especially important for performance & reliability. This proprietary MotoSport guide walks you through every step of the process – and offers model-specific tips every CRF125FB owner should know.
Why Coolant Changes Matter on Your CRF125FB
- Maintains optimal operating temperature, preventing overheating and power loss.
- Protects the aluminum radiator and engine internals from corrosion and scale buildup.
- Prevents coolant system failure that could leave you stranded between motos.
Tools & Supplies Needed
- Fresh, ethylene glycol-based coolant labeled safe for aluminum radiators (never use standard automotive coolant with silicates)
- 5mm Allen key for side panel removal
- 10mm socket, ratchet
- Drain pan
- Funnel
- Shop towels
- New crush washer for the drain bolt (recommended for best seal)
- Phillips screwdriver (for radiator cap retainer)
Step-by-Step Coolant Change Procedure
- Allow the engine to cool fully. Never attempt this service on a hot bike.
- Remove plastics to access service points.
- Using a 5mm Allen key and 10mm socket, remove the seat and left side panel. On the CRF125FB, this gives access to the radiator and the drain bolt on the water pump cover.
- Put a drain pan under the water pump area (lower right side of engine).
- Loosen but do not remove the radiator cap.
- Remove the small Phillips screw holding the radiator cap in place, then loosen the cap (this helps air in, for faster draining).
- Locate and remove the coolant drain bolt at the base of the water pump housing.
- Remove the bolt and let coolant drain fully into your pan. If equipped, remove the drain bolt's washer and replace it with a new crush washer before reinstallation.
- Optional: Gently tilt the bike from side to side to help remove all old coolant.
- Reinstall the drain bolt (with new washer if possible) and torque to spec.
- Pour fresh coolant into the radiator using a funnel.
- Fill until just below the lip of the filler neck. Squeeze the lower radiator hose to burp out air bubbles.
- Replace the radiator cap securely and reinstall the cap retainer screw.
- Start the engine and let it idle for several minutes to circulate the new coolant.
- Shut off the engine and let cool, then double-check coolant level.
- Top off as needed. Do not overfill – a proper fill means the coolant is just under the neck when cool.
- Reinstall side panels & seat, and wipe up any spills before hitting the trail.
MotoSport Expert Tips for the 2015 CRF125FB
- The CRF125FB's coolant system is simple, but be careful not to strip plastic fasteners or over-tighten the radiator cap.
- Always use a silicate-free coolant formulated for aluminum – standard car coolant can corrode the lightweight system in your bike.
- This model's drain bolt is easy to reach, but always use a new crush washer for leak-free peace of mind.
- Coolant should be changed at least every two years, or annually if you ride hard in mud, sand, or extreme heat.
- If coolant appears rusty or sludgy, flush the system with distilled water before adding new coolant for best results.
Final Reminders
- Dispose of old coolant properly – never pour it down drains or onto the ground.
- Test ride to check for leaks, and verify your radiator cap is secure before enjoying your next ride.
A well-maintained cooling system means more ride time and fewer problems. For parts, fluids, and crush washers specific to your 2015 Honda CRF125FB, remember to shop parts for a 2015 Honda CRF125FB Dirt Bike.
Related Shopping Categories
Shop Radiators for a 2015 Honda CRF125FB Dirt Bike.
Shop Coolant for a 2015 Honda CRF125FB Dirt Bike.
Shop Temperature Sensors for a 2015 Honda CRF125FB Dirt Bike.
Shop Tools for a 2015 Honda CRF125FB Dirt Bike.
Shop Radiator Hoses for a 2015 Honda CRF125FB 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.