How to Change the Coolant in a 1990 Suzuki RM250
Shop parts for a 1990 Suzuki RM250 Dirt Bike.
Changing the coolant in your 1990 Suzuki RM250 is a crucial maintenance step that protects the engine from overheating and corrosion while ensuring optimal performance on the track or trail. The RM250 has a two-stroke liquid-cooled engine – proper coolant care keeps it running at peak power. This guide walks you through a safe, effective coolant change tailored to your RM250, plus a few model-specific notes to keep your vintage Suzuki race-ready.
Tools and Supplies Needed
- New coolant formulated for aluminum motorcycle engines (check MotoSport for recommendations)
- Distilled or deionized water for flushing
- Socket or wrench set (8mm commonly needed)
- Drain pan and funnel
- Clean rags and gloves
- Replacement radiator cap or hoses if inspection reveals cracks or wear
Step–by–Step Coolant Change Instructions
- Let the bike cool completely. Hot coolant is pressurized and can cause burns.
- Remove the right side panel and, if fitted, the skid plate for easy access to the water pump and radiators.
- Set a drain pan beneath the water pump on the lower right side of the engine.
- Remove the radiator cap to break the system vacuum and allow coolant to drain freely.
- Locate and remove the water pump drain bolt (8mm bolt on the water pump cover). Allow coolant to drain fully into the pan–dispose of old coolant responsibly.
- Flush the system: Pour distilled water into the radiator and let it drain through the open water pump bolt. Repeat until water runs clear. Avoid using tap water due to mineral content.
- Reinstall and torque the water pump bolt to spec. Check for any leaks or signs of gasket wear.
- Slowly refill the radiator with new coolant, carefully tipping the bike side-to-side to burp out trapped air. Fill to the base of the filler neck.
- Reinstall the radiator cap securely.
- Start the bike and let it idle for a few minutes, watching the coolant expand and circulate. Shut off and allow the engine to cool completely.
- Recheck coolant level: Top off as needed once the coolant contracts and any air bubbles escape.
Special Tips for the 1990 RM250 Owner
- The RM250 does not have a coolant reservoir tank–all checks and fills are done at the radiator neck.
- Regularly inspect radiator hoses for aging, cracking, or softness. Suzuki recommends replacing hoses and coolant yearly for best reliability–this is especially critical on vintage bikes to prevent leaks during hard riding.
- When reinstalling the water pump cover, check the condition of the paper gasket – replace if torn or brittle to avoid leaks.
- Always use a coolant compatible with magnesium & aluminum; avoid automotive antifreeze with silicates which may damage RM250 engine internals.
Periodic Maintenance Reminder
- According to Suzuki service schedules, change coolant after the initial break-in and then at least once per year, or whenever the system is serviced or stored long-term.
Keep your 1990 RM250 running cool & strong by making routine coolant changes a part of your maintenance regimen.
Related Shopping Categories
Shop Radiators for a 1990 Suzuki RM250 Dirt Bike.
Shop Coolant for a 1990 Suzuki RM250 Dirt Bike.
Shop Temperature Sensors for a 1990 Suzuki RM250 Dirt Bike.
Shop Tools for a 1990 Suzuki RM250 Dirt Bike.
Shop Radiator Hoses for a 1990 Suzuki RM250 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.