Changing your Coolant in Six Simple Steps

It’s a daunting task, but just like every other system on your bike your coolant needs periodic attention and changing. Your motorcycle’s manufacturer likely recommends replacing the coolant every two years, or 24,000 miles, but make sure that you check your user manual for your motorcycle's coolant replacement interval. If you leave it unchanged, the murky (or brownish) coolant can deteriorate your cooling system’s performance. This means your bike will run hotter, give you less power, and wear out key components faster. Make sure you regularly change your coolant – it is cheap insurance.

If it seems a bit overwhelming, don’t fear: here we will go over detailed instructions on changing the coolant in your bike. This guide works for most motorcycles, but keep in mind that some bikes will have specific steps not covered here; we recommend checking your bike’s manual before beginning any maintenance. You can also get in touch with one of Motowheel’s experts to help guide you!

Step #1. Let your bike completely cool off before beginning

Before you open the radiator cap, make sure that the engine is cool to the touch. A hot engine will have scalding coolant in it. If you open up a hot radiator the superheated coolant can spray out or pour out on you, resulting in serious burn injuries.

Keep in mind that most coolants contain toxic ethylene glycol, so don’t ever pour used coolant down the drain or into the gutter. Always make sure to dispose of used fluids properly. Also, your pets may be tempted to lick the sweet-tasting coolant and they will get very sick from it. It is safer to use products with non-toxic propylene glycol if you can find them.

Step #2. Remove the body parts so you can get to the radiator cap

Changing coolant is an easy job on a naked bike where the radiator cap, reservoir tank, and drain bolts are out in the open. Unfortunately, all of these parts are behind body panels on sport and touring bikes, which you must uninstall prior to changing the fluids. Rather than tackling your coolant replacement as a standalone task, you should consider combining it with other systems that need maintenance – such as changing your air filter or your spark plugs. Also, make sure you inspect the radiator hoses for cracks or damage while they are exposed.

Step #3. Drain the coolant

Once you uninstall the bike's panel, you'll need to find the drain bolt for the cooling system, which is typically at the bottom of the water-pump cover. The drain bolt will have a copper sealing washer. Once you identify the drain bolt, place a drain pan under it and then unscrew the bolt. The fluid will dribble out slowly until you crack the radiator cap, and then it will come pouring out (see point #1!). As the objective is to get rid of all the old coolant, you must also drain the reservoir tank. To drain the tank, you will probably need to uninstall it, rinse it out with tap water, and reattach it.

Step #4. Flush the radiator

If you notice that your coolant is extremely discolored, don't give a second thought to flushing your radiator with a hose. Rinse the radiator with the water. Also, check the hose clamps for cracks and tightness, and take a look at your radiator fins, too. A few can be bent or damaged, but a badly banged-up radiator has lost much of its effectiveness and should be replaced or repaired.

Step #5. Refill radiator and coolant

Once you flush the radiator, slap a new sealing washer on the drain bolt and tighten it to the proper torque specification. Now it’s time to add coolant back into the system. Most products are ready to use, but if you buy a concentrated one, you may need to mix it with distilled water in a 50/50 ratio. Do not mix your coolant with tap water – it can leave deposits inside the radiator's delicate tubes. Reinstall the drain bolt and pour in fresh coolant to the top of the filler neck.

Step #6. Test the system

Once you fill the system up to the radiator neck, leave the cap off. Start the bike and let it run for a minute or two and then rock the bike back and forth gently to help coax the air out of the system. Blip the throttle to burp out any remaining air. Recheck the fluid level, top it off again and then cap the radiator. Move on to the overflow reservoir and fill it to the upper line.

Once you cap the radiator tank, make sure to reinstall any bodywork that you uninstalled. Then you are good to go!

Take your used fluids to dispose of it at the nearest auto parts store or your town's recycling center. Also, it is never a terrible idea to recheck your coolant levels after your first ride.

Do you need to know more about coolants or have any questions? Get in touch with Motowheels at 916.369.2509 or

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