Quick Maintenance: Changing Motorcycle Coolant

Flushing and changing out coolant or antifreeze on a motorcycle or any other powersports vehicle is a pretty basic maintenance job a beginner can handle. 

Like changing the engine oil, a coolant change is a good task for a novice mechanic to get hands-on experience doing maintenance on a machine. Here are the basics to changing the coolant on a motorcycle.

Motorcycle Coolant Change Preparation

First, have your tools ready, such as a ratchet and extensions, sockets, pliers, screwdrivers and Allen wrenches.

The tools you’ll need will depend on the machine you’re working on, but most coolant changes only require a handful of basic tools. As for supplies, besides the coolant of course, have latex gloves, a drain pan ready to catch the coolant that drains out, and shop towels to catch and clean up coolant spills.

Motorcycle Coolant Change: The Basics

Put the motorcycle up on a rear stand or side stand and make sure the engine is cold. 

Find and open the radiator filler cap at the top of the cooling system. You may have to disconnect or remove some parts such as the seat, the fuel tank and hoses first on some motorcycles to access the fill cap. Place a drain pan under the bike before you unscrew the coolant drain bolt at the bottom. Be prepared for some coolant to spill out, and make sure you have gloves on, as coolant is a toxic substance. Keep children and pets away while you’re doing the coolant change and from the liquid itself at all times.

Next, remove the drain bolt and let the coolant empty out into the drain pan. You don’t have to completely remove the drain bolt in most cases, but if you do, make sure you don’t lose the washer that comes with it. After the cooling system is completely drained, reinstall the plug and its washer, and torque it to the specs provided in the service manual. Pour the old antifreeze into an empty container you can use to transport it to a recycling center. 

Flush out the cooling system before refilling it with new coolant to remove any dirt or debris inside it. When filling the cooling system with a 50/50 mix of coolant and water, make sure you mix the solution first before pouring it into the filler. Make sure you only use distilled water, or use a ready-to-go pre-mixed coolant instead. 

Slowly fill the cooling system to the brim, then run the engine with the radiator filler cap off. Bubbles and a level drop in coolant are normal as the engine warms up. Top off the cooling system as the level keeps dropping, occasionally rocking the bike from side-to-side gently to remove air trapped in the system. Once the coolant starts to expand out of the filler, stop the engine and replace the radiator cap. 

When the radiator is completely full, run the engine on idle for a minute, then re-check the coolant level and top it off again if necessary. After the coolant level is full, take the bike for a short ride to get it completely up to temperature, then park the bike and allow it to cool off. Check the level again and top it off if necessary.

These are just the basics to changing out the coolant on a motorcycle. Keep in mind that the process will vary by motorcycle make and model, so make sure you check your specific bike’s service manual for the correct specs.