How to Change the Coolant in a 1991 Honda CR250
Shop parts for a 1991 Honda CR250 Dirt Bike.
Keeping your 1991 Honda CR250 running cool is essential for optimal performance on and off the track. The coolant system, while robust for this era of CRs, requires regular maintenance – particularly since overheating can cause severe internal wear. Here is a MotoSport-exclusive, step-by-step guide for changing the coolant on your CR250, ensuring a trouble-free process every time.
Tools & Supplies Needed
- Phillips and flathead screwdrivers
- 8mm & 10mm sockets with ratchet
- Catches or drain pan (for old coolant)
- Fresh coolant (Honda HP Coolant or compatible pre-mix recommended for aluminum radiators)
- Funnel
- Rags and safety gloves
Step 1: Preparation – Safety First.
- Allow the engine to cool completely before you start. Pressurized hot coolant can cause injury.
- Place your dirt bike on a stable stand and ensure it is secure and level.
Step 2: Remove Seat, Tank, and Side Panels
- To gain proper access to the radiators and related hoses, use your socket set and screwdrivers to remove the seat, the gas tank, and if necessary, the radiator shrouds.
Step 3: Drain Old Coolant
- Locate the radiator cap – ensure it is cool to the touch, then remove it to relieve pressure.
- Find the coolant drain bolt on the water pump cover (typically a 10mm bolt, located on the right side of the engine, below the kickstarter).
- Position your catch pan under the drain bolt and carefully remove the bolt. Allow the old coolant to fully drain from both the engine and radiators.
- If desired, disconnect the lower radiator hose to facilitate faster draining.
- Inspect the drain bolt's washer and replace it if damaged.
Step 4: Flush the System (Optional, but Recommended)
- For routine changes, a flush with distilled water can help remove residue. Pour clean distilled water into the radiator, reinstall the drain bolt, run the engine briefly, then drain again.
Step 5: Reinstall Drain Bolt & Hoses
- Reinstall the drain bolt with washer. Tighten to spec – avoid over-tightening to prevent stripping threads in the soft aluminum.
- If any hoses or clamps are worn or cracked, now is a good time to replace them.
Step 6: Refill with Fresh Coolant
- With a funnel, slowly pour the new coolant into the radiator until nearly full.
- Tip the bike side-to-side to help air escape while filling.
- Reinstall the radiator cap.
Step 7: Bleed the Cooling System
- Start the bike and let it idle with the radiator cap off for a minute to purge remaining air; you may need to top up slightly as air escapes.
- Once bubbles cease and coolant is steady at the filler neck, top off if needed and securely replace the cap.
- Check under the bike and around hoses/bolts for leaks.
Step 8: Reassemble & Double-Check
- Reinstall the gas tank, seat, and panels. Tighten all fasteners as needed.
- After first ride, with the bike cool, re-check coolant level and add as needed.
1991 Honda CR250-Specific Notes
- The 1991 CR250 uses aluminum radiators and a magnesium water pump cover, so always use coolant designed for aluminum engines to prevent corrosion.
- Check the radiator cap for proper sealing; a weak cap can cause overheating on this vintage model.
- If you regularly ride in hot climates or race hard, consider upgrading to high-efficiency radiators and silicone hoses, both available here at MotoSport.
- Monitor the water pump area for seepage; 1991 CR250s are known for gasket wear with age.
Changing the coolant at least once a year or after any major engine work will keep your 1991 Honda CR250 running strong and prevent breakdowns mid-ride. For all your parts and coolant needs, MotoSport has you covered.
Related Shopping Categories
Shop Radiators for a 1991 Honda CR250 Dirt Bike.
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Shop Temperature Sensors for a 1991 Honda CR250 Dirt Bike.
Shop Tools for a 1991 Honda CR250 Dirt Bike.
Shop Radiator Hoses for a 1991 Honda CR250 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.