Motorcycles have an internal combustion engine that works at high temperatures, and this temperature can cause the machine and other metal parts to overheat. To prevent your engine from getting overheated, a cooling system is built in your motorcycle.
Every rider should be familiar with understanding the working principle behind motorcycle cooling systems so to be able to recognize if the system is working correctly or if some issues need to be fixed.
So how does a motorcycle cooling system work? A cooling system prevents your engine and its metal parts from overheating. It cools the engine using an air or water cooling system. Air cooling uses wind power to cool your engine, while the water system uses a coolant that cools the engine by circulating coolant between the engine and radiator.
A motorcycle cooling system is not some complex or difficult motorcycle system, quite the opposite, and I think that after reading this article, you will know everything necessary about the motorcycle cooling system and realize how simple it actually is.
Table of Contents
Working Principle Behind Motorcycle Cooling System
The motorcycle engine needs to be warmed to work at its optimal levels and prevent any of its components from wearing out or getting damaged. The cooling system is not only responsible for cooling your engine once it reaches the hottest temperature and that way prevents it from overheating, but your cooling system also helps your engine to reach the optimal temperature and warm up as fast as possible and then remains on that optimal working temperature on which it functions the best.
Have you ever thought about what would happen if your engine’s cooling system didn’t function the way it should? It would lead to overheating, which could make the cylinder head gaskets explode or, in the worst case, crack the engine blocks if the issue is pretty serious. The cooling system takes care of this heat and prevents any of this from happening.
Note: If your cooling system doesn’t work, what will happen is the pistons will weld inside of your motorcycle’s cylinders, and unfortunately, you will have to take off your entire engine and repair it, or in the worst-case scenario, throw it and buy a new engine. Even if you are capable of fixing the engine, the cost of the entire repair will probably be very expensive, and buying a new engine will seem like a much better solution.
Tip: Don’t be like some riders and think, ohh a cooling system is something I don’t need to give much attention to because that is far from the truth. You need to treat the cooling system as your engine system and any other vital bike component.
When Do I Need to Change The Coolant in My Motorcycle (Liquid-Cooled)
You can look at your coolant, and it may seem good and that it could last more years or miles, but it doesn’t matter if the previous conditions were met (either mileage or years); you need to change it. As a general rule, motorcycle coolant needs to be changed every two years or 23,000-25,000 miles. Also, if you notice that your coolant has a strange and unusual color and looks brownish or murky, you must drain and replace it immediately.
Note: Take a motorcycle manual and see your motorcycle’s specifics and how long your coolant replacement interval is.
If you need to change your motorcycle coolant, click on this link to learn how it needs to be done.
What Is a Motorcycle Coolant?
A motorcycle coolant is a liquid that keeps your motorcycle engine from overheating, and that way prevents any engines inside parts like pistons to get worn and torn, or in case of pistons, it prevents high temperature to weld pistons to the cylinders and does significant damage to your motorcycle engine.
Water is a great choice for lowering the temperature. However, you need to be careful if you pour water inside your coolant tank during the winter period because temperatures below freezing will freeze the water turning it into ice which expands and will damage your coolant system. We use antifreeze to prevent this from happening, which stops ice from forming. Most liquid-cooled bikes use a mixture of antifreeze and water in a 50/50 ratio to get heat out of the engine through the radiator.
There are different types of antifreeze, and various formulations will give you other benefits. You can get antifreeze with a higher boiling point or increased corrosion resistance. Most antifreeze is made of ethylene glycol, a toxic antifreeze component, or propylene glycol, a non-toxic component.
Cooling System Components
Radiator
A radiator is responsible for heat exchanging for your motorcycle engine. The radiator changes temperature with the hot water that comes from the motorcycle engine and mixes it with the air. It has a sealed cover, a drainage port, an outlet port, and an inlet port. Aluminum is mainly used to make radiators that lower their weight.
Water Pump
The water pump sends the cooled water or coolant from the radiator back to your engine, the cylinder block, cylinder head, and heater core. The water is then sent from the engine back to the radiator again, where it gets cooled, and the cycle repeats again.
Thermostat
A thermostat has a function and behaves as a valve for the coolant, and it sends the coolant through the radiator only when a specific temperature has been reached. The thermostat has an essential role in controlling the temperature of the internal combustion engine and regulating that that temperature is optimal at all times.
Cover gasket (Timing Head)
It stops and prevents mixing antifreeze, oil, and cylinder pressure by sealing major engine parts.
Freeze Plugs
A steel plug is made to seal cylinder heads and cylinder block openings that are created during the casting process. They can pop out during the winter season if there isn’t any frost protection.
Radiator Overflow Tank
This plastic tank is usually placed next to the radiator (every bike can have slight differences). It has an inlet connected to one overflow hole and the radiator. This tank is the same one where you pour water before you go riding.
Hoses
Hoses are responsible for connecting the radiator with the engine, and they are the component of the cooling system through which the coolant flows. You need to check these hoses periodically or on any leaking sign because they are prone to leaking after a couple of years of use.
Why Do I Need to Change Motorcycle Coolant?
Motorcycle coolant needs to be changed because the ingredients that the coolant is made of can break down, and it can lose its properties, and its functionality will decrease, which means that the cooling system won’t work as it suppose to. Dirt can develop in the coolant resulting in it getting dirty. It will lead to lowering coolants performance, which directly impacts your motorcycle cooling system and your entire motorcycle.
What Motorcycle Coolant Is the Best for My Motorcycle?
The answer to this question mainly depends on your motorcycle’s make and model. Every rider needs to look into his motorcycle manual to determine which motorcycle coolant is suitable for his bike, and no, you don’t need to worry about getting the best coolant possible on the market. The only thing that matters when getting the proper coolant is that it meets the specific written in your motorcycle manual or if you don’t have a manual search for it online.
Note: I mostly use the same coolant for my Kawasaki Z750 that was in the bike before the liquid change, but this is just my habit. You don’t need to do the same.
How Do I Maintain the Coolant in My Motorcycle?
Take your motorcycle manual and look for your coolant’s specifications. If you don’t have a motorcycle manual, look on the internet for what your motorcycle has the most significant benefit from. If you have any friends riding a similar bike, consult them for a piece of advice, and don’t worry about getting the best coolant possible on the market, it is just important that it meets the specifications written in your motorcycle manual.
Can I Use Car Coolant for My Motorcycle?
It all depends on your motorcycle type. If the coolant you use for your car meets the standards written in your motorcycle manual, you can use it; just make sure to avoid silicates.
CAUTION: Don’t risk pouring your car’s coolant into your motorcycle just to spare some time or money if you are not sure that your motorcycle can take the same coolant that you use for your car care. Make sure that you are 100% right that your car’s coolant can be poured into your motorcycle as well.
Air and Water Cooling Systems
The main difference between these two cooling systems is that the air cooling system is dry and doesn’t use liquid to operate. In contrast, the water cooling system uses liquid (water, antifreeze, or both) to function.
A Water Cooling System
The water cooling system uses liquid, whether it be water, antifreeze, or in some cases both, to cool motorcycle engines. This system has a radiator that radiates the heat out of the water or antifreeze circulating through the engine. It also has a thermostat built into the passageway that connects the engine with the radiator. This thermostat is used to control the coolant flow ( water, antifreeze) into the radiator.
An Air Cooling System
The air cooling system uses the engine cylinder structure, which has cooling fins around the cylinder and on top of the piston-cylinder head. Cooling fins are responsible for drawing heat out of the cylinder. The air is driven over these fins when a rider is in motion, and the heat gets scattered.
Here is a nice video explaining the difference between air and water cooling systems:
Pouring the Coolant
The coolant is poured into the filler neck of your cooling system through a funnel that will help you pour the coolant much easier. Don’t hurry while pouring the coolant to prevent any spills, rather do it slowly in a way to pour some amount of coolant in the funnel and then wait for it to get in the system (you will hear the system getting filled by the recognizable gurgling sound it produces while getting poured).
It may happen that you won’t be able to pour the total capacity of your motorcycle tank, but that is perfectly normal; what you will do is leave the radiator cap off and ignite the motorcycle and leave it idle for a couple of minutes. Rev your throttle a few times since that way; you will shake out any air left in the radiator and system. After doing that, turn off your motorcycle and recheck your coolant level. If you need to fill coolant, you need to do it and pour it as much as necessary, so the coolant is to the full line.
Return on the radiator cap, and your motorcycle is ready for another ride.
How to Dispose of Your Motorcycle Coolant?
This chapter is as important as the previous ones regarded your coolant.
Please don’t dispose of your motorcycle coolant somewhere in the environment and nature because you will do a lot of damage to plants and animals to which the coolant is very toxic.
Please dispose of your motorcycle coolant in a local disposing center that will take care of it correctly and adequately. That way, you will protect both animals and plants and the entire nature and environment. You should never pour your coolant down the drain or somewhere in the ground.
Final Thoughts
This article covered the basics that every rider and motorcycle lover should know, especially if they intend to change the motorcycle coolant. The cooling system is not a very complex system to understand, and I think that in this article, you will learn everything you need to know about it, starting from what it is in the first place to how and where to dispose of it.