There are three main filters in a Daihatsu Hijet, The Air Filter allowing particles to be separated from clean air. The Fuel filter separates dirt particles in the fuel from entering the carburetor. The Oil Filter separates particles from the oil. Clean oil maintains the life of the Daihatsu Hijet Engine. The Clean fuel maximises the life of the carburetor allowing clean fuel to enter the engine. Clean air allows the engine to run smooth and last longer. The Daihatsu Hijet will perform at its best with clean air, fuel and oil. Filters should be changed on a regular basis. This enhances peformance and fuel economy.