How to Change the Coolant in a 1990 Suzuki RMX250: MotoSport Proprietary Guide
Shop parts for a 1990 Suzuki RMX250 Dirt Bike.
The 1990 Suzuki RMX250 is built for tough trails and demanding riders, but its longevity depends on regular cooling system maintenance. Routine coolant changes keep your bike running cool – and prevent costly internal damage over time. Here's the definitive, MotoSport.com-exclusive guide to changing the coolant in your RMX250.
Why Change Your Coolant?
- Coolant breaks down over time, losing its ability to lubricate and prevent corrosion.
- The RMX250's high-performance engine relies on effective cooling, especially for aggressive off-road riding.
- Suzuki recommends a yearly coolant change, plus flushing for overhaul or storage.
Tools & Supplies Needed
- 8mm socket or wrench (for drain bolt)
- Phillips screwdriver (for skid plate & radiator cover, if equipped)
- Coolant drain pan
- New coolant (ethylene glycol-based, premixed for motorcycles)
- Distilled water (for flushing)
- Rag or shop towels
- Gloves & eye protection
Coolant Change Procedure – Step by Step
- Ensure engine is cool. Never open the radiator cap on a hot engine.
- Remove seat and side panels for easier access if equipped. Optional: Remove skid plate for better access to drain bolt.
- Remove radiator cap. This allows air to enter & speeds draining.
- Locate water pump drain bolt (bottom of right crankcase cover, near water pump housing). Use an 8mm wrench to loosen the drain bolt. Place a drain pan directly beneath.
- Allow coolant to fully drain. Tilt the bike side-to-side if needed.
- Flush system. Pour distilled water into the radiator, replace cap, and re-loosen the drain bolt to flush out sediment and any old coolant. Repeat until water runs clear. Do not use tap water – minerals can clog the system.
- Reinstall drain bolt. Tighten securely (do not over-tighten as the threads are aluminum).
-
Fill radiator with new coolant. Pour slowly to prevent air bubbles.
If your RMX250 has a coolant overflow tank, be sure to fill to “Full” mark. - Replace radiator cap. Start engine and let idle for 2-3 minutes. Shut down and allow engine to cool.
- Recheck coolant level. Top off if needed – air pockets may burp out on first run.
- Inspect for leaks. Pay special attention to drain bolt and hose connections.
Model-Specific Notes for RMX250 Owners
- Check hoses annually – replace if brittle, cracked or swollen.
- The RMX250 uses remote reservoir radiators – inspect mountings for damage after any crash.
- Flush system before winter storage or after any major engine work.
- Overheating risk: Mud & debris can clog RMX radiator fins – clean these frequently.
Coolant Type & Capacity
- Use motorcycle-specific coolant, ethylene glycol-based and premixed with deionized water.
- Never use plain water – inadequate boil protection & corrosion risk.
- Capacity: Refer to owner's/service manual for exact volume; expect ~1 quart (~0.95 liter) per radiator system.
Disposal & Eco-Friendly Tips
- Dispose of old coolant at an approved recycling center. Do not dump it – it's toxic to pets & wildlife.
Regular coolant changes keep your 1990 RMX250 in peak condition for years of epic rides – and prevent the most common causes of premature engine wear. Should you need any new radiator hoses, water pump components, or coolant, Shop parts for a 1990 Suzuki RMX250 Dirt Bike.
Related Shopping Categories
Shop Radiators for a 1990 Suzuki RMX250 Dirt Bike.
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Shop Temperature Sensors for a 1990 Suzuki RMX250 Dirt Bike.
Shop Tools for a 1990 Suzuki RMX250 Dirt Bike.
Shop Radiator Hoses for a 1990 Suzuki RMX250 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.