How To Flush and Change Your Motorcycle Coolant?

How To Flush and Change Your Motorcycle Coolant

If you’re a new motorcycle owner, then you might have already heard that regular motorcycle coolant flushing is one of the rituals you’ll be performing on your new baby.

This not only helps keep your engine in top working condition but also extends the life of your motorcycle.

But the real riddle is, how exactly do you flush the coolant of your motorcycle?

Being a completely new thing, you might have no idea where to start.

In the following guide, we’ll take you through the A-Z process on how to change your motorcycle engine coolant. We tried making this guide as easy as possible to make it easy for absolute beginners to comprehend.

Why Do You Need To Change Your Motorcycle Coolant?

Before we get into more details, let’s first discuss why it’s important to change the coolant of your motorcycle regularly. (We said this is an A-Z guide, so we’ll not leave out any detail you need to know about flushing your motorcycle coolant).


FIRST…it’s worth keeping in your mind that the coolant/anti-freeze in your motorcycle helps dissipate excess heat produced by your motorcycle engine, especially during the hot summer months, to keep it cool.

If your bike engine gets hot and you don’t get rid of the excess heat, your motorcycle might will become clouded with failures that will be far costlier to repair than simply replacing the coolant.

After some period of keeping your motorcycle engine cool, the antifreeze will accumulate debris and other undesired contaminants. These make it turn from being helpful to being destructive…the fluid can cause corrosion, rusting, scales formation, and other debris in your motorbike engine.

This is where a coolant flush comes in…

It involves FORCING a couple of gallons of a cleaner, water, and your new coolant through the system to help get rid of ALL the old antifreeze and all the debris and contaminants it might have built up.

You might argue that simply draining is all you need to get rid of this old coolant. But this method will not be quite effective…it’ll still leave some of the old coolant behind (plus its contaminants), which will then mix with your new antifreeze, pollute it and cause overheating.

Apart from getting rid of the old coolant, the extra benefits of flushing the coolant includes removing the rust and scales that have built up on your radiator. It also helps lubricate and extend the life of your water pump.

Using the right coolant can also help keep off future leaks, foaming, debris accumulation, and foaming.

What are Signs You Need a Motorcycle Flush?

Generally, replacing the coolant of your motorcycle should be done after around every 2 years or 24,000 miles. However, this period can be less or more than 2 years, depending on the type of coolant you’re using. (different types of antifreeze have different lifespans).


You should check your user manual will help you know the frequency of coolant change for your specific motorcycle.

That said, there are some tell-tale signs that you might want to look out for to help you determine if it’s time to get rid of the old coolant.

These signs include:

  • If your motorcycle is overheating, then it means it might be contaminated in a way, or there’s a leak in the coolant system.
  • Even if the coolant seems to be full, but you still experience overeating on your motorcycle, it’s a good idea to flush the old antifreeze
  • If you witness your motorcycle coolant leaking underneath your two-wheeled machine, it’s time to perform a flush
  • Visible debris in your coolant, grinding/knocking engine noise, and steam or odd smell rising from the hood are additional signs of deteriorated coolant.

Steps To Flush Motorcycle Coolant

In this section, we’ll get into the step by step details on how to perform a motorcycle coolant flush on your own…

Things you’ll need for this job:

  • New motorcycle coolant
  • Philips screwdriver or wrenches
  • Drain pan
  • Safety gear: goggles, gloves, and mask
  • Water source (and a hosepipe)

Steps to follow:

Step #1: prepare your motorcycle for flushing

The number one thing you’ll need to do is prepping your motorcycle for the flushing job.

Don’t panic, though.

Prep work here doesn’t mean taking apart your entire motorcycle…it’s pretty simple as you just need to access your radiator cap.

Depending on which bike you own, you’ll be required to take off the fainting and the gas tank for easy access to your radiator.

Sports bikes, in particular, require you to take off the fairings to access your motorbike radiator.

Step #2: Drain the old, deteriorated coolant

Once you locate the radiator, put on the safety gear and get down to removing the old coolant,

Grab a screwdriver or wrench to help you loosen then drain bolt.

Again, this step will depend on the design of your specific motorbike.

Some models come up with up to 4 drain bolts, and you’ll have to loosen all of them in this step.

You might also discover that your bike has an air bleeder bolt on the water pump. Or it features up to two radiators, all of which will need to be worked on.

So, it’ll be a big plus if you take time to understand your machine beforehand (your user manual will come in handy!)

ENSURE you have the drain pan located right under your motorcycle to collect the old coolant. Then, remove the radiator cap (to help release any system pressure, and facilitate easier coolant flow), take out all the dram bolts plus the air bleeder bolt.

Give the old coolant time to flow out of your motorcycle.

Safety Note: Ensure the coolant is cold before performing this step. You don’t do this right after you have come from a trip, when the coolant is still hot, as it can burn your hands.

Step #3: Clean your motorcycle radiator

Once the old coolant stops flowing, put all the bolts (including the air bleeder bolt) back in to prepare the radiator for some cleaning.

Cleaning the radiator is as simple as filling it with water, with the help of your garden hose, and then loosen the bolts to help drain the water.

You’d want to repeat this step severally until the water flowing out looks clear.

The next thing you’ll need to do is cleaning the overflow bottle. You do this by disconnecting the hose running from your motorcycle radiator neck all the way to the overflow bottle

Then, you can take out the overflow tube for easy cleaning.

Vigorously clean the bottle using your tap water to help eliminate all the sludge at the bottom. When the water runs clear, it means the bottle is clean. Let it dry completely before taking it back.

You’d also want to clean the bolts and washers to eliminate any remaining traces of the old coolant and its contaminants.

Step #4: Drain ALL the air from your radiator

If you have been wondering what’s the job of the air bleeder bolt on your motorcycle, this is where it comes in.

It helps you easily bleed all the air inside your motorcycle radiator before filling it with the new coolant.

If you don’t get rid of this air, it’ll end up creating hot air pockets in your system, which will result in your bike overheating. In the worst cases, it can cause cavitation, which can result in serious engine damage.

To drain the air from your radiator:

Remove the air bleeder bolt and let the air drain out of the water pump. When it’s done, run your motorcycle engine and let it run for long enough to open the thermostat and release any extra air trapped.

When you’re satisfied that no air is remaining in the system, turn off your motorcycle engine. And take back the air bleeder bolt.

Step #5: Refill your motorcycle with the new coolant

The last step involves filling your motorcycle radiator with the new coolant.

But before you do this, you’d want to do one final check to ensure you’ve screwed back in all the bolts, the overflow bottle is in place, and the connecting hose is securely in place.

Grab your new coolant and fill the overflow bottle up to the full line. Consider using a funnel to prevent spills and make the refiling faster.

And as you fill the bottle, make regular pauses to allow any remaining trapped air to escape.

Finally, close and tighten the radiator cap. You might consider checking the coolant level after 1-2 days and top it up as necessary.

IMPORTANT: If you’re diluting your own anti-freeze, be sure to use 100% distilled water for the job as regular tap water contains minerals and contaminants. Also, use the right proportions of anti-freeze (50%) and pure water (50%).

Clean any coolant that might have spilled on the motorcycle body as it can easily corrode the plated metal parts.

Motorcycle antifreeze/coolant is HIGHLY toxic, so ensure your kids and pets don’t come anywhere near your working area. Likewise, store any reaming coolant in a secure place, away from the kids and pets.

That’s it! You’re done flushing and changing your motorcycle coolant in 5 easy steps!

How To Dispose of The Old Radiator Fluid?

Now that you have finally flushed out all the old coolant from your motorcycle coolant, you might be wondering what to do with it.

As we have just stated above, the anti-freeze is highly toxic. If you go through its list of ingredients, you’ll discover it features ethylene glycol as the major component, a substance that’s HIGHLY poisonous to humans.

This means you shouldn’t dispose of the old coolant anyhow!

You should NOT pour it down the drain or on the toilet. Make sure it doesn’t get into contact with your skin.

The BEST way to dispose of the hazardous old antifreeze is to transfer it into a sealable plastic container and put ‘used coolant or ‘dangerous’ label on them and safely transport them to a local hazardous waste disposal or recycling facility.

If you have no idea of any nearby facility, you can contact your local government office or mechanics garage for more info.

Still at it, if you make any spills during the coolant flushing/changing process, make sure you absorb it immediately.

Using baking soda, sand, or kitty litter will help you absorb as much liquid as possible. Next, spread the entire area with paper towels and let it settle for 1-2 hours to absorb the smaller traces of this poisonous substance.

Toss all the absorbent materials used to clean the mess into a sealable plastic bag and place it in your outdoor trash bin, where kids and pets can’t easily access it.

One more thing…clean the affected area by spraying some liquid soap on it and then scrub it with a sponge or scouring pad. Let the area air dry.

How Often Should You Flush The Coolant?

As we mentioned earlier on, experts recommend you to change your motorcycle coolant after around every 2 years (or after covering 2400 miles) for continued effectiveness.

That said, the lifespan of your motorcycle can vary depending on the brand as well as the operating conditions.

Standard coolants usually have a lifespan of 2 years, while the extended-life coolants from premium brands can last for up to 5 years.

You should also consult your bike’s user manual to see if the manufacturer offers you any maintenance schedule recommendations.

What if You Don’t Do a Radiator Flush?

Not changing your motorcycle coolant will only invite more problems.


As you already know, the motorcycle coolant tends to deteriorate with time. By the time it’s ripe for change, it already has become accumulates a lot of debris and become contaminated with various substances.

Failure to change will make it continue accumulating debris and becoming more acidic.

Keeping the old coolant inside your engines for longer will give it more to cause corrosion and damage the interior of your engine, radiator, and water pump.

​According to, not changing the coolant can also cause the coolant hoses to deteriorate over time. They might show signs of internal cracking or even become soft and bulge.

As you can see, ignoring this crucial maintenance exercises on your bike will cause it to develop problems that will cost you more to fix than buying that can of anti-freeze.

Even if you stay in an area that has no freezing weather, let nobody fool you that you don’t need an antifreeze. It’ll help protect your motorbike system from metal corrosion, raise the boiling point, and even lubricate your water pump.

When buying that new anti-freeze, make sure you buy the right product for your motorcycle.

Keep these factors in mind to help you chose the right product:

  • Look for an ethylene-glycol based anti-freeze that contains no silicates. Silicates can seriously wear down your motorcycle impeller blades.
  • Coolants made for aluminum alloys are suitable for your motorcycle as most motorbike manufacturers use aluminum material for the engines.
  • If it’s your first time changing the coolant, go for a pre-mixed product. Otherwise, you’ll have to dilute it with water in 50:50 proportions before using it
  • NEVER use car coolants on your motorcycle. Stick to motorcycle-specific products
  • Check your bike coolant capacity in advance to help you pick the right amount of coolant. Most bikes have a capacity of 3-5 liters.

Final Thoughts

One of the most important maintenance tasks you’ll need to do on your new motorcycle regularly is replacing the coolant.

This is because the coolant degrades with time, accumulating debris and contaminants that can seriously damage your motorcycle engine and cause corrosion, rusting, scaling. The result is frequent motorcycle failures, which will cost you more to repair.

The ideal replacement frequency for motorcycle coolants should be at least every 2 years or after every 24000 miles.

After going through our beginner-friendly, 5-step guide above, you should be able to flush out the old coolant on your motorcycle and replace it with a new one on your own.

Always remember to use the ideal type of coolant. And use your user manual as the primary reference for this maintenance task.

Have you started working on your motorcycle already?

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