01
Viscosity and flow
- SAEสมาคมวิศวกรยานยนต์
- The body behind the viscosity grades for engine oil (J300) and gear oil (J306) — grades such as 5W-30 come from here.
- WWinter
- The letter after the first number marks cold performance — the lower the number, the better the oil flows on a cold start.
- cStเซนติสโตกส์
- The unit of kinematic viscosity, usually quoted at 40°C and 100°C. Higher means thicker.
- VIดัชนีความหนืด
- How much viscosity changes with temperature — higher is more stable. Synthetics usually beat mineral oils here.
- HTHSความหนืดที่อุณหภูมิสูงและแรงเฉือนสูง
- Measured at 150°C under high shear — it shows whether the film survives when the engine is hot and loaded. Unit: cP.
- ISO VGเบอร์ความหนืดอุตสาหกรรม
- The grading system for hydraulic and industrial gear oils, based on viscosity at 40°C — for example ISO VG 46.
- Pour Pointจุดไหลเท
- The lowest temperature at which the oil still flows; below it the oil is too stiff to pump.
- Flash Pointจุดวาบไฟ
- The temperature at which vapour can ignite. A higher value means less evaporation and more margin when hot.
02
Standards and approvals
- APIสถาบันปิโตรเลียมอเมริกัน
- Engine oil quality standards: petrol grades start with S (SN, SP), diesel grades with C (CI-4, CK-4).
- ACEAสมาคมผู้ผลิตรถยนต์ยุโรป
- The European standards: A/B for passenger cars, C for vehicles with after-treatment, E for heavy-duty trucks.
- ILSACคณะกรรมการมาตรฐานน้ำมันหล่อลื่นสากล
- The US/Japanese standard — GF-5, GF-6 — adding fuel-economy requirements on top of API.
- JASOมาตรฐานยานยนต์ญี่ปุ่น
- Used for motorcycle oils: MA/MA2 for wet clutches (no slip), MB for scooters with dry clutches.
- NLGIสถาบันจาระบีแห่งชาติ (สหรัฐฯ)
- The grease consistency scale — the higher the number the stiffer the grease. NLGI 2 is the common wheel-bearing grade.
- OEMมาตรฐานของผู้ผลิตรถ
- A car maker’s own specification — MB 229.51, VW 504 00, Dexos. Some vehicles accept nothing else.
03
What the oil is made of
- Base Oilน้ำมันพื้นฐาน
- The bulk of the lubricant, sorted into Groups I–V by purity and viscosity index.
- VHVI / YUBASEเบสออยล์ดัชนีความหนืดสูงมาก
- SK’s own Group III stock with a viscosity index above 120 — the core of ZIC oils.
- PAOโพลีอัลฟาโอเลฟิน
- A Group IV synthetic stock with excellent heat and cold performance, used in top-tier oils.
- TBNค่าความเป็นด่างรวม
- How much acid the oil can neutralise. Higher suits diesels or high-sulphur fuel; it falls as the oil ages.
- SAPSเถ้าซัลเฟต ฟอสฟอรัส กำมะถัน
- The ash-forming content. Vehicles with exhaust filters need low-SAPS oil or the filter clogs early.
- DPFกรองดักเขม่าดีเซล
- The soot filter on modern diesels — it only tolerates the oil the maker specifies.
- EPสารรับแรงกดสูง
- Additives that react with metal to protect under heavy load, found in gear oils and greases such as CROWN GREASE EP 2.
- Syntheticสังเคราะห์
- Oil built on synthetic or Group III stock. “Semi-synthetic” is a blend with mineral oil.
You will find these values on each of our product pages under Typical Properties and Specification.
Adapted with permission from the technical material of SK Enmove (skzic.com) · Standard values referenced from SAE J300, SAE J306 and ISO 3448