Of course, if it gets any hotter, it can cause wear and tear on the engine and the internal components. That’s why there must be a cooling system to deal with excessive heat.
Most motorcycle engines are either air- or liquid-cooled – each one with its own pros and cons.
- Differences between air-cooled vs. liquid-cooled engines – how they work and pros and cons of each type
- What forced-air cooling is
- What coolant consists of – and whether motorcycle coolant is the same as car coolant
- What’s an air-cooled engine, and how does it work?
- What is liquid cooling?
- What is “coolant” and what’s in it?
- Coolant FAQs
Prefer to get this information in podcast form? Listen to the 30 Minute Motorcycling Podcast episode about air-cooled and liquid-cooled engines:
What’s an air-cooled engine, and how does it work?
Some powerful engines use an air and oil cooling system, where the oil is sprayed onto the bottom of the piston crowns by small jets.
Benefits of air-cooled engines
It’s therefore common to see air-cooled engines on small mopeds and motorcycles.
Disadvantages of air-cooled engines
The engine’s still running, but since you’re not moving, there’s no air going into the vents on the engine – therefore, the engine isn’t cooled.
Furthermore, since the air temperature can vary, so can the cooling. For example, on a really hot day, the engine will receive hot air while you’re riding, which isn’t as effective as cold air.
Forced air-cooling means that the engine has a fan inside which is run by power from the engine.
However, while this gives a more stable cooling, engine power is lost, since the engine has to provide power to the fan – which also adds extra weight to the bike.
However, underneath, the engine is actually a liquid-cooled engine, with its radiator cleverly disguised.
What is liquid cooling?
The coolant is circulated through the engine through a water jacket, which cools off the cylinders by dosing the hot parts.
In addition to this, the coolant is also responsible for preventing corrosion and lubricating the water pump among other things.
Benefits of liquid-cooling
Disadvantages of liquid cooling
Since a liquid-cooled system also needs components like a water pump and a water jacket, the overall weight of the bike also increases.
What is “coolant” and what’s in it?
What is anti-freeze for?
In colder parts of the world (e.g., Canada, Midwestern USA, and Norway), the coolant would freeze during the winter if it was 100% water.
And if the coolant freezes, not only will it not do its job, but it can also cause damage to the engine itself.
Therefore, the anti-freeze lowers the freezing point. A standard mixture of 50% water and 50% anti-freeze has a freezing point of -33 Celcius or -27 Fahrenheit.
However, with a mixture of 60% anti-freeze and 40%, it’s possible to get a freezing point as low as -38 degrees Celcius or -36 degrees Fahrenheit.
Is Motorcycle Coolant The Same as Car Coolant?
Has Your Coolant Gone Brown?
If your coolant has turned brown, it could mean that you have a blown head gasket.
Remember this saying:
“If your coolant is green, you’ve got a healthy machine. If it’s milkshake brown, you’re in blown head gasket town”