What are the types of engine oil and their differences?

[DelAngela]

Automotive engine oils are divided into three types: conventional mineral oil, semi-synthetic oil, and full synthetic oil. The differences lie in performance, usage conditions, and price. Conventional Mineral Oil: Mineral oil is a commonly used lubricant in the market. It is derived from the distillation process of petroleum, where useful substances like gasoline and aviation fuel are separated, and the remaining base oil is further processed. Essentially, it utilizes the inferior components of crude oil. Mineral oil is inexpensive, but its lifespan and lubrication performance are inferior to synthetic oils, and it also causes significant environmental pollution. Additionally, due to the inability to completely remove impurities during the refining process, mineral oil has a higher pour point, making it unsuitable for use in low-temperature regions or extreme conditions. Semi-Synthetic Oil: Semi-synthetic oil is made from semi-synthetic base oil, which is a purified product of mineral oil through hydrocracking technology. It is a blend of mineral oil and full synthetic oil in a 4:6 ratio. The purity of semi-synthetic oil is very close to that of full synthetic oil, but its cost is slightly higher than mineral oil, making it an ideal transitional product between mineral oil and synthetic oil. Full Synthetic Oil: Full synthetic oil is the highest-grade engine oil. It is derived from ethylene and propylene, which are dispersed from natural gas or crude oil, and then undergoes complex chemical reactions like polymerization and catalysis to form a lubricating fluid composed of large molecules. Essentially, it uses the superior components of crude oil, subjected to chemical reactions and controlled to achieve the desired molecular structure. Full synthetic oil molecules are neatly arranged, giving them strong resistance to external variables. As a result, it has excellent thermal stability, oxidation resistance, and viscosity stability, far surpassing mineral oil and semi-synthetic oil, but it also comes with the highest price.

[SanLondon]

I've been fixing cars for over 20 years, so I know this inside out. Engine oils fall into three main categories: mineral, semi-synthetic, and full synthetic. Mineral oil is the cheapest, like basic fuel – fine for old Santanas but needs changing every 5,000 km. Semi-synthetic is an upgraded version of mineral oil with additives, perfect for family cars like the Sagitar, with changes every 7,000-8,000 km. Full synthetic is premium stuff – high-purity base oil with excellent high-temperature protection, a must for turbocharged engines or luxury cars like BMW, Benz, and Audi, lasting over 10,000 km. In winter when it's cold, go for 0W or 5W grades; here in northeast China, I always recommend 0W for quicker cold starts. In summer, use oils with higher second numbers like 40. If an old car burns oil, just switch to higher viscosity.

[MatteoMarie]

From a materials engineer's perspective, the core difference in engine oils lies in their base oil composition. Mineral oils are derived from direct petroleum distillation with uneven molecular sizes, making them prone to solidification at low temperatures and decomposition at high temperatures. Semi-synthetic oils blend Group III base oils (hydrocracked) with small amounts of Group IV PAO, offering more balanced flow properties and oxidation resistance. Full synthetic oils use Group IV PAO or Group V ester-based oils with uniform and stable molecular structures, achieving pour points as low as -60°C. Current mainstream SP/GF-6 certified oils contain more phosphorus and sulfur-limited additives, making them more compatible with particulate filters. When selecting oil, first check the manufacturer's recommended ACEA standard – Volkswagen vehicles require 504/507 certification, while American cars look for the Dexos label.

[LeLayla]

A while ago, I researched car maintenance for my own vehicle. Mineral oil is like non-dairy creamer milk tea—low cost but not very healthy. Semi-synthetic oil is like regular fresh milk tea, offering a balance between cost and performance. Full synthetic oil is like handcrafted fresh milk tea, made with premium ingredients. When changing the oil, the mechanic taught me to read the SAE rating: the number before the 'W' represents low-temperature fluidity. For my small car in the south, 5W-30 is sufficient. The number after, like 30 or 40, indicates high-temperature viscosity. Newer cars benefit from thinner oil for better fuel efficiency, while older cars need thicker oil for better sealing. Remember, turbocharged cars must use full synthetic, while naturally aspirated engines can save money with semi-synthetic.

[SanEverett]

Pro tips from seasoned drivers: Mineral oil turns black right at 5,000 km, while full synthetic stays crystal clear even at 8,000 km. The difference lies in base oil cleanliness—full synthetic's additives dissolve more carbon deposits. 0W-20 is most fuel-efficient for Japanese/Korean cars, while German cars generally require 5W-40. Remember two certifications when changing oil: Look for the latest SP grade in API certification, and ACEA's C5 low-ash standard for European cars. Switch to lower winter viscosity before northern winters, or face dry engine starts at dawn. GPF-equipped vehicles must use low-ash oil to avoid costly particulate filter clogs. Never cut corners with off-brand oils.

[CalvinLynn]

Hot Tip: Current China VI-compliant vehicles divide engine oils into three major camps. European cars promote low-SAPS 0W-20/30 oils to protect GPFs. American models prefer fuel-efficient Dexos1-certified oils. Japanese vehicles continue using GF-6 standards. The key difference lies in anti-wear additive formulations—traditional oils contain sulfur-phosphorus-zinc compounds while modern oils switch to calcium-magnesium detergents. Using wrong oil may trigger check engine lights!

Attention tuners: Track oils prioritize high-temperature shear stability but may cause carbon buildup in daily driving. High-mileage vehicles benefit from molybdenum-containing oils that repair wear (identifiable by blue fluorescence). Always check certification icons on bottles rather than trusting influencer recommendations.