What do the 'five oils, four filters, and three waters' refer to?

[KhloeFitz]

Five oils, four filters, and three waters refer to: 1. Five oils refer to engine oil, power steering oil, transmission oil, clutch oil, and brake oil; 2. Four filters refer to oil filter, air filter, cabin air filter, and fuel filter; 3. Three waters refer to windshield washer fluid, coolant, and battery water. The functions of engine oil are: 1. To reduce friction and high temperatures; 2. To minimize gas leakage and prevent external pollutants; 3. To prevent water, air, acidic harmful gases, and contact with components; 4. To cushion the rising pressure in the engine cylinder port; 5. To flush away dirt generated on the working surfaces of components. The functions of transmission oil are: 1. To keep the gear system clean; 2. To lubricate the transmission device.