The heat dissipation of motorcycle air-cooled engine is to use natural wind to directly cool the engine. The water-cooled engine of motorcycle uses the coolant around the water tank and the cylinder to exchange through the water pump to cool the engine. The oil-cooled engine of motorcycle is oil-cooled, which uses the vehicle's own oil to dissipate heat through the oil radiator.

What kind of cooling method each motorcycle uses depends on the motorcycle design factors. There is still a difference in performance between these three cooling methods.

(1) Motorcycle air-cooled engine

Advantages: Zero failure of the cooling system (natural cooling) Air-cooled engine has low cost and occupies less space.

Disadvantages: Slow heat dissipation and is limited by the engine form. For example, inline 4-cylinder engines rarely use air cooling. The middle 2 cylinders cannot effectively dissipate heat, so air cooling is only suitable for 2-cylinder engines.

In fact, air cooling is cooling by the wind brought by the vehicle. The cylinder barrel of the air-cooled engine will be designed with a large heat sink, and the cylinder head will be designed with a fan heat sink and air duct (many air-cooled engines are single-cylinder engines or V2 engines with low speed and high torque). If an air-cooled engine with no design defects runs long distances, there will be no problem at all. There is no saying that air cooling is not suitable for long distances. Many Harleys are air-cooled and have not had any seals due to high temperatures.

Air cooling is the standard configuration for daily commuting vehicles. The cooling system has zero faults and the engine cost is low. As long as it is properly maintained, there will be no high temperature problems. On the contrary, water-cooled vehicles have more high temperature problems. In short, air cooling is completely sufficient for single-cylinder, low-speed vehicles. There is no need to worry about long-distance problems.

(2) Water-cooled motorcycle engine

Advantages: It can effectively control the temperature of high-power and high-speed engines. When the temperature is low, the throttle valve of a water-cooled vehicle will be closed until the oil temperature rises to achieve the best lubrication effect. When the temperature is high, the throttle valve will open the water tank to start working. When the temperature is too high, the fan will turn on to cool down the engine to the optimal operating temperature. This is the standard working principle of water cooling.

Disadvantages: high cost, complex structure, high failure rate, and large space occupied by the external water tank.

Motorcycle water-cooled engine is a cooling method with relatively good heat dissipation effect. The principle of water cooling is to cool down the cylinder liner and cylinder head by wrapping the cylinder liner and cylinder head with flowing water. The basic accessories of water cooling are water pump, water tank temperature control and fan.

Water cooling is a necessary cooling system for multi-cylinder high-power and high-speed engines (there is also water-oil dual cooling). Small-displacement 125 single-cylinder vehicles basically do not need water cooling, and generally 125 cannot generate so much heat. However, water cooling systems are now being reduced in displacement, and many 150CC motorcycles are already equipped with water cooling systems.

(3) Motorcycle oil-cooled engine

Advantages: obvious heat dissipation effect and low failure rate. Low oil temperature can reduce the viscosity of the oil at high temperature.

Disadvantages: There are restrictions on the amount of engine oil. The oil radiator cannot be too large. If it is too large, the oil will flow into the oil radiator, resulting in insufficient lubrication at the bottom of the engine.

Oil cooling is the use of the car's own oil to dissipate heat through the oil radiator (the oil radiator and the water tank are basically the same thing, but one is oil and the other is water). Because the circulation power of the oil cooling comes from the engine's oil pump, the oil cooling only needs an oil fan heater (oil tank). High-end oil cooling will be equipped with a fan and a throttle valve.

The oil cooling system is generally equipped for mid-range street cars, pursuing stability and fanning effect. Single-cylinder air-cooled cars are more suitable for oil cooling. To change the oil cooling of a single-cylinder air-cooled car, you only need to add an oil fan heater in the middle of the oil channel.

How to distinguish between oil cooling and water cooling?

First of all, the heat sink of the oil cooling radiator is very thick, and the heat sink of the water cooling radiator is very thin. The size of the oil cooling radiator is generally very small, and the water cooling radiator is larger. If your car has both radiators, then look at the larger one, which is the water cooling radiator.

There is another very important distinction above. Most water cooling radiators have electronic fans behind them, but oil cooling radiators basically do not. (However, the radiator of some two-stroke vehicles does not use electronic fans).

What are the advantages and disadvantages of oil-cooled vehicles and water-cooled vehicles?

Oil-cooled vehicles: It is equipped with a radiator similar to the cooling water tank of water-cooled vehicles, and the oil in the engine is circulated externally to reduce the temperature. Compared with water-cooled vehicles, its structure is also much simpler. Since the oil that lubricates the engine parts is directly cooled, the heat dissipation effect is also better, which is worse than air-cooled vehicles, but not as good as water-cooled vehicles.

Water-cooled vehicles: The structure is complex, and the cylinder block, cylinder head and even the engine box must be redesigned (compared to the same air-cooled vehicle). It requires a special water pump, water tank, fan, water pipe, temperature sensor, etc. It is also the most expensive and larger in size, but it has the best cooling effect and even cooling.

Do oil-cooled vehicles need to add antifreeze?

Everyone knows that general water-cooled radiators now need to add antifreeze, so do oil-cooled vehicles need it?

Of course not. Since it is oil-cooled, it means that the cooling liquid in the engine is oil, not water. So no water is needed. However, some cars use both oil and water cooling. In that case, don't be fooled by the oil-cooled radiator. Check to see if there is a water tank radiator. If there is, be sure to add antifreeze.