How to Change the Coolant in a 2018 Suzuki RMZ250: Complete Guide
Shop parts for a 2018 Suzuki RMZ250 Dirt Bike.
Changing the coolant on your 2018 Suzuki RMZ250 is a crucial maintenance task that protects engine components and ensures reliable performance, particularly under demanding motocross conditions. This guide from MotoSport explains everything you need to know, with specific procedures tailored to the unique features of the RMZ250.
What Makes the 2018 RMZ250 Cooling System Unique?
- Features an aluminum radiator, cylinder, and cylinder head; only use coolants formulated for aluminum to avoid corrosion and internal clogging.
- Capacity is approximately 950 ml of coolant, similar to most MX bikes from the same era.
- Coolant should be checked regularly and replaced yearly for optimal performance and longevity.
Required Tools & Supplies
- New coolant rated for aluminum radiators (Suzuki Coolant or high-quality equivalent, 50:50 mix with distilled water is recommended)
- Drain pan
- Socket set (to remove radiator drain bolt)
- New drain bolt washer/gasket
- Shop towels/rags
- Protective gloves and eye protection
Step-by-Step Coolant Change Procedure
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Preparation
Place your RMZ250 on a stand, ensuring the engine is cool. Remove plastics as necessary for clear access to the radiator cap and hoses. -
Remove Radiator Cap
Slowly unscrew the radiator cap to relieve pressure. Set the cap aside on a clean surface. -
Drain Old Coolant
Position a drain pan underneath the water pump (left side of the engine). Locate and remove the coolant drain bolt & washer, typically found on the lower water pump cover. Allow all coolant to drain. Observe fluid color – any heavy discoloration or particles suggest it is past due for a flush. -
Flush (Recommended for Overdue or Contaminated Coolant)
If old coolant is dirty or you are switching coolant types, reinstall the drain bolt, fill the radiator with distilled water, run the engine for a minute, and then drain again. Repeat if necessary for a clear rinse.
For a deeper flush, remove radiator hoses and carefully use compressed air if desired, but never force high pressure through the system. -
Replace Washer & Bolt
Install a new washer on the drain bolt and torque it to spec. Do not overtighten. -
Refill with New Coolant
Pour the 50:50 coolant mix into the radiator slowly. Gently rock the bike side-to-side to help release trapped air. -
Bleed the Cooling System
Some RMZ models include a small air bleeder bolt on the cylinder head or top of the radiator. Loosen the bleeder slightly until a steady stream of coolant (no bubbles) appears, then retighten.
If unavailable, simply run the engine with the cap off until all bubbles stop surfacing, then shut off and top up as needed. -
Replace Radiator Cap and Check for Leaks
Secure the cap tightly – ensure it clicks in place. Start the bike again, let it warm up, and inspect for any leaks around hoses or the drain bolt. -
Re-Check Coolant Level
Once the engine cools, verify the coolant remains at the proper level and top off if necessary.
Important Tips Specific to the 2018 RMZ250
- Only use coolant with corrosion inhibitors suitable for aluminum – improper fluid can result in internal damage and loss of cooling performance.
- The RMZ250 has a lightweight, high-efficiency radiator system. Regular flushing and proper filling techniques help prevent overheating, especially in race environments.
- Consult your bike's owner's manual for torque specs on the drain bolt and to check for year-specific features, such as air bleeder bolts or hose routing changes.
Final Reminders
- Dispose of old coolant responsibly—never pour down drains or onto the ground.
- Check hoses for cracks or swelling while the bike is disassembled; replace worn components promptly.
Related Shopping Categories
Shop Radiators for a 2018 Suzuki RMZ250 Dirt Bike.
Shop Coolant for a 2018 Suzuki RMZ250 Dirt Bike.
Shop Temperature Sensors for a 2018 Suzuki RMZ250 Dirt Bike.
Shop Tools for a 2018 Suzuki RMZ250 Dirt Bike.
Shop Radiator Hoses for a 2018 Suzuki RMZ250 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.