機油黏度等級詳解
SAE 標號如 5W-30 含兩個數字。W 前的數字表示低溫泵送性能，W 後的數字表示高溫時的黏度。請按汽車廠家針對你所在氣候的建議選擇標號。
| 標號 | 低溫(W) | 高溫黏度 | 典型用途/氣候 |
|---|---|---|---|
| 0W-16 | W = winter; flows at very low temp | Very low hot viscosity | Hybrid/modern engines; best fuel economy, mild climates |
| 0W-20 | Winter rating, pumps cold to -40C class | Low hot viscosity | Newer petrol engines; cold climates, fuel saving |
| 5W-20 | Winter grade, good cold flow | Low hot viscosity | Many US/JP petrol engines; moderate climates |
| 5W-30 | Common winter grade | Medium hot viscosity | Most modern petrol/diesel; wide climate range |
| 0W-30 | Winter grade, very cold flow | Medium hot viscosity | Cold regions; long-drain modern engines |
| 5W-40 | Winter grade, broad use | Higher hot viscosity | Turbo petrol/diesel; hot climates, towing |
| 10W-30 | Pumps at moderately cold temp | Medium hot viscosity | Older engines; temperate climates |
| 10W-40 | Standard winter grade | Higher hot viscosity | Older/high-mileage engines; warmer areas |
| 15W-40 | Needs warmer start | High hot viscosity | Diesel, trucks, older engines; hot climates |
| 20W-50 | Thick, warm-start only | Very high hot viscosity | High-temp, heavy load, older V8; hot climates |
說明
- 務必以車輛手冊為準；機油過稠會影響油耗與冷啟動。
- 合成油比礦物油在寬溫範圍內更穩定保持等級。
常見問題
- 5W-30 裡的 W 是什麼意思？
- W 代表冬季（winter）；前面的數字（5）表示機油在低溫下的泵送等級，於低溫測試。
- 哪個數字是高溫黏度？
- W 後的數字（30）是高溫黏度等級，在 100°C 下測定。
- 可以用比推薦更稠的油嗎？
- 不建議。過稠會降低油耗表現且冷啟動流動差，請遵循廠家規格。
- 0W-20 比 5W-30 更好嗎？
- 沒有絕對更好；0W-20 低溫流動性好、省油，但只可用引擎允許的標號。