认识机油的API

对机油有点认识（但不很精通）的驾车人士，大概都知道机油有不同的浓度。大多数新车普遍使用较稀薄的机油，而对于行驶了100,000km的车子，专家们都建议使用20w-50浓度的机油。

“20“和”50“代表什么，这里我就不说了。因为这次要分享的主要课题是机油的API。

我们购买机油，除了要买最合适引擎的浓稠度(更专业一点，叫做SAE Grade)之外，也要注意机油的API标准。

相信各位有留意到，同样的SAE Grade，只是不同品牌，价格也会相差几块到二三十块不等。为什么？就是API的区别在作怪。

API的级别，有SM, SL, SJ, SH, SG, SF....越高的标准（如SM），表示该机油达到更严格的要求。因为最近才察觉到这微妙之处，所以我暂时只能在网站寻找机油的技术规格，还没去调查价钱。

• PETRONAS Mach 5, API SM
• MOBIL Super XHP, API SL
• SHELL Helix Super, API SL (Yellow bottle, no more available)
• PENNZOIL GT Performance Plus, API SJ (Blue bottle)
• ENEOS Super Asia, API SJ
• IDEMITSU Racing, API SJ
• SHELL Helix HX3, API SJ (Red bottle)
• SHELL X100, API SG (White bottle)
• PENNZOIL MGMO, API SG (Golden yellow bottle)
• CASTROL GTX Extra, API SG
• ESSO Extra Motor Oil, API SF

我本身向来信赖SHELL Helix黄桶装。直到两年前，这款机油似乎突然绝迹了，到处都找不到，油站也没卖了。当时看到同样也是20w-50的X100，就买了。虽然脑子一直在想着为什么会变便宜了（因为当时万物涨价），但还是倒进去引擎了。现在回想起用着X100的那段日子，确实好像比较“吃黑油”，一桶4公升用得刚刚好5000km，颜色呈深棕色。

后来有一次有急事要出远门，随随便便在临近一家维修店换机油。该店的机油只有独孤一味Castrol，根本没得选。呸！这是我用过最差的机油！用没到3000km机油就快变“黑油”了。最后是跑到4000km我又换回了Shell X100。

几个月前把车子送去洗的时候看见Shell机油的poster，才发现原来20w-50的机油“改革”了！由黄桶变红桶，名字叫HX3。我才买了PENNZOIL GT Performance Plus (API SJ) ，等下一次oil change就要派上用场了。HX3就再等下下次才试用吧！

Glossary:

Society of Automotive Engineers (SAE) - defines oil according to its viscosity. Oil can be monograde or multigrade, depending on its viscosity performance at various temperatures. Multigrade oils are able to maintain their performance in high and low temperatures and are defined by two numbers. The first (followed by a W) indicates the lubricant's viscosity under lower temperatures. The second and higher number indicates the lubricant's viscosity under greater temperatures.

American Petroleum Institute (API) - classifies oils according to their capacity to protect the engine. The letter S is used for petrol engines and the letter C for diesel. The letter that follows the S or the C indicates the degree of performance and protection, with A the lowest and X highest. Some oils can be used in petrol and diesel engines, so their classification is stated as SJ/CF or CF-4/SJ.

Detailed information about engine oil grades can be obtained here.