How to Change Coolant in a 1987 Yamaha XT350 – A MotoSport Exclusive Guide

Shop parts for a 1987 Yamaha XT350 Dirt Bike.

If you own a 1987 Yamaha XT350, maintaining the cooling system is critical for reliable performance on trail or street. This guide walks you through a safe, thorough coolant change tailored specifically to this classic dual-sport. The XT350 uses a liquid-cooled, single-cylinder engine, with a reputation for rugged reliability but also for holding onto air pockets and requiring careful maintenance.

Before You Start

  • Work on a cool engine–Never open or drain the cooling system when the engine is hot, as pressurized hot coolant can cause severe burns.
  • Gather supplies: drain pan, funnel, appropriate pre-mixed motorcycle coolant (or mix with distilled water if concentrate), rags, safety gloves, and a 10mm socket or wrench.
  • Locate the radiator cap, coolant reservoir, and drain bolt (typically a 10mm bolt on the steel coolant pipe near the water pump).

Step-by-Step Coolant Change Procedure

  • Remove the seat and necessary side panels to access the radiator cap and overflow reservoir. This makes filling and checking levels easier.
  • Place a drain pan beneath the lowest point of the cooling system, usually the drain bolt on the steel pipe that leads from the cylinder to the water pump. This bolt has a washer between the pipe flange and the bolt head.
  • Remove the radiator cap to allow air in, which helps coolant drain freely. Then loosen and remove the drain bolt. Allow old coolant to fully drain.
  • Reinstall the drain bolt with a fresh washer if needed. Tighten securely but do not overtighten.
  • Slowly refill the radiator with fresh coolant up to the filler neck. For the XT350, pour in slowly and allow the air to purge naturally.
  • Loosen the pump purge (bleeder) bolt just slightly. Allow trapped air to escape until only coolant seeps out, then retighten. This step is specific to many Yamaha models and especially important for the XT350 to prevent overheating due to airlocks.
  • Top up the coolant reservoir to the full mark.
  • Start the bike and let it idle with the radiator cap off–blip the throttle and gently rock the bike to help any remaining air bubbles move out. Watch for settling and add coolant if needed.
  • Install the radiator cap and heat cycle the engine completely. Let it reach normal operating temperature. Shut it off and allow it to cool fully. Recheck coolant level in the reservoir and radiator, topping off if necessary.
  • Dispose of old coolant properly at a recycling center–never pour it down the drain or onto the ground.

XT350-Specific Tips & Reminders

  • The XT350 has a compact radiator that is more susceptible to clogging and overheating if the coolant system is not properly maintained or bled. Always take extra time to purge air from the system, especially at the pump bleeder.
  • Use only pre-mixed or properly diluted motorcycle coolant–never substitute automotive coolant unless it is specifically marked as motorcycle-safe and phosphate-free, to avoid internal corrosion.
  • Check for leaks at the drain bolt, radiator cap, and hose connections before your next ride.
  • If you notice any repeated loss of coolant or overheating, carefully recheck for trapped air or possible leaks.

Changing the coolant as part of routine XT350 maintenance will help preserve your ride's performance and engine longevity–keeping you ready for any adventure. For replacement parts, gaskets, or coolant, shop parts for a 1987 Yamaha XT350 Dirt Bike.

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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.