What are the substances in engine oil?

[Harmony]

Engine oil contains substances that are carefully proportioned additives blended by engineers. Engine oil, also known as engine lubricant, consists of two main components: base oil and additives. The base oil is the primary constituent of the lubricant and serves the following functions: 1. Cooling and temperature reduction; 2. Sealing and leak prevention; 3. Cleaning and purification; 4. Shock absorption and cushioning; 5. Lubrication to minimize wear; 6. Rust and corrosion prevention; 7. Component protection. The method for changing engine oil is as follows: 1. Use a jack to lift the vehicle, locate the drain plug, and loosen it to drain the oil; 2. Remove the oil filter, place a container beneath it, and drain the old oil; 3. Install a new oil filter and add fresh engine oil.

[GabriellaLynn]

I've been repairing cars for over a decade, and engine oil may seem simple but has deep intricacies. Over 70% of it is base oil, divided into mineral oil (cheaper but shorter lifespan) and synthetic oil (more expensive but durable). The remaining 20% consists of precious additives: anti-wear agents act like liquid armor coating the gears; detergents function like tiny brushes cleaning sludge; viscosity index improvers prevent oil from thickening in cold weather or thinning in heat; antioxidants serve as preservatives against deterioration; anti-foam agents specifically tackle stirred-up bubbles. Last time, a car owner's engine still shook after an oil change. Upon disassembly, we found metal shavings – clearly the inferior oil's anti-wear additives couldn't withstand high temperatures and turned to debris. Switching to proper full synthetic oil immediately solved the issue.

[SanKathryn]

During car maintenance, technicians often say engine oil is the lifeblood of the engine. So what's in this 'blood'? Base oil makes up the bulk, like a soup base divided into bone broth (mineral oil) and chicken broth (synthetic oil). The key lies in the additive package: anti-wear agents are usually zinc-phosphorus compounds, forming a protective film on metal surfaces under high temperatures; detergents like alkylphenol amines specifically dissolve carbon deposits; viscosity modifiers such as polymethacrylates ensure flow even at -30°C. Once saw someone cheap out with a no-name brand oil—5,000 km later, sludge clogged the oil passages like sausages, costing 8,000 in major repairs. Penny wise, pound foolish.

[OFelicity]

I was shocked when I first learned about motor oil composition! Conventional mineral oil is directly refined from petroleum, semi-synthetic oil is blended with chemically synthesized components, and full synthetic oil is basically lab-created. The most amazing part is the additives: molybdenum offers three times better anti-wear performance than traditional zinc; borate detergents can dissolve turbocharger carbon deposits under high temperatures; silicone antifoam agents eliminate foam in just 1 minute. During my last high-altitude road trip, my friend's car using conventional oil suffered severe thermal breakdown, while my car with ester-based full synthetic oil had a noticeably smoother engine sound when climbing - the principle is that ester molecules remain more stable at high temperatures and can even repair microscopic metal surface scratches.