What does 'Five Oils, Four Filters, and Three Liquids' mean?

[VanAndrew]

Five Oils, Four Filters, and Three Liquids respectively refer to: 1. Five oils refer to engine oil, power steering fluid, transmission oil, clutch fluid, and brake fluid; 2. Four filters refer to the oil filter, air filter, cabin air filter, and fuel filter; 3. Three liquids refer to windshield washer fluid, coolant, and battery fluid. The functions of engine oil are: 1. To reduce friction and high temperatures; 2. To minimize gas leakage and prevent contamination from external pollutants; 3. To prevent contact between water, air, acidic harmful gases, and engine components; 4. To cushion the pressure rise in the engine cylinder ports; 5. To clean away dirt generated on the surfaces of engine components. The functions of transmission oil are: 1. To keep the gear system clean; 2. To lubricate the transmission components.

[MaverickDella]

I've been driving all my life, and I remember my instructor emphasizing the old saying 'five oils, four filters, three waters' when I first learned to drive, which refers to the basic items of car maintenance. The five oils include engine oil, transmission oil, brake fluid, power steering fluid, and differential oil, which are responsible for lubricating and protecting critical components. The four filters are the air filter, oil filter, fuel filter, and cabin air filter, which remove impurities and debris from the air and oil. The three waters are coolant (also called antifreeze), windshield washer fluid, and battery water—though many cars now use maintenance-free batteries instead. Why is this important? I once neglected regular oil changes, and it cost me over a thousand dollars to fix the resulting engine problems. In routine maintenance, checking these items every six months or 10,000 kilometers can extend your car's lifespan. Don't see it as a hassle; an old car, like a person, needs care to keep running safely and reliably for years to come.

[LaJackson]

I've worked in an auto repair shop for several years and often come across the term 'five oils, four filters, three fluids,' which refers to five types of oils, four filters, and three fluid maintenance items. The five oils specifically are engine oil, transmission fluid, brake fluid, power steering fluid, and gear oil. The four filters are the air filter, oil filter, fuel filter, and cabin air filter. The three fluids refer to coolant, windshield washer fluid, and battery electrolyte or battery water. These components keep the car running smoothly—for example, a dirty air filter can cause the engine to ingest dust and lose power. Car owners often forget to change the transmission fluid, leading to rough shifting. It's recommended to follow the maintenance manual to save money and avoid major repairs. During maintenance, a quick check with simple tools can solve many issues—don’t wait until warning signs appear and end up spending unnecessarily.

[Winifred]

When I first bought the car, I asked the 4S store staff what it meant, and he said 'Five oils, four filters, and three fluids' is a car maintenance mantra. The five oils include engine oil, transmission oil, etc., the four filters such as air and oil filters, and the three fluids include coolant and windshield washer fluid. This list covers the engine, braking, and cleaning systems, ensuring the car runs smoothly. After my first maintenance, I clearly felt the power restored, and maintenance is actually quite routine. I recommend beginners to learn it, as basic maintenance saves both trouble and money.