Where is the engine oil added in a car?

[OLucille]

The location for adding engine oil is generally on the left side of the engine, marked with an oil can symbol on the cap. Open this cap to add oil. When adding oil, refer to the engine's oil dipstick to ensure the amount is neither too much nor too little. Normally, the optimal oil level is slightly above the midpoint between the two marks on the dipstick. The functions of engine oil: Lubrication: There is rapid relative sliding between pistons and cylinders, as well as between main shafts and bearings. To prevent excessive wear, an oil film must be established between these sliding surfaces. A sufficiently thick oil film separates the surfaces, reducing wear. Auxiliary cooling: Engine oil has a low specific heat and does not inherently cool the engine. However, during operation, it carries heat back to the oil pan, where it dissipates into the air, aiding the radiator in cooling the engine. The actual cooling is done by the water (or antifreeze) outside the engine housing. Cleaning: High-quality oil carries away carbon deposits, sludge, and metal particles from engine parts through circulation, cleaning the surfaces as it flows. Sealing: Oil forms a seal between piston rings and pistons, reducing gas leakage and preventing contaminants from entering. Rust and corrosion prevention: Lubricant adheres to part surfaces, protecting them from water, air, acids, and harmful gases. Shock absorption: When cylinder pressure spikes suddenly, the load on pistons, piston rings, connecting rods, and crankshaft bearings increases sharply. The lubricant on these bearings helps cushion the impact. Anti-wear: Adding lubricant between friction surfaces reduces the coefficient of friction, lowering resistance, saving energy, and minimizing wear. It also helps prevent abrasive wear, surface fatigue, and adhesive wear. Precautions: Check the packaging. Genuine oil containers have one-time-use caps with foil seals bearing the manufacturer's unique marks. Counterfeit oil may lack these features. Authentic oil also has special markings in inconspicuous places like the label, can bottom, inner cap, or handle. Comparing packaging can help spot fakes. Inspect the oil. Genuine oil is light, transparent, free of impurities, suspended particles, or sediment, and flows smoothly when shaken. Fake oil may appear darker, contain impurities or sediment, have a strong or irritating odor, flow poorly when shaken, or feel sticky to the touch.