API is mentioned on our Technical Data Sheet. But what do API SQ and API CK-4 mean exactly?

The American Petroleum Institute (API) is the authority when it comes to setting standards for motor oils used in petrol and diesel engines. Petrol (gasoline) engines are classified under Category S, indicating "Spark Ignition", while diesel engines fall under Category C, indicating "Compression Ignition". Each category is followed by a letter, reflecting the oil's technological advancements.

For petrol (gasoline) engines, API specifications range from SA to SH, with higher letters representing newer technologies. Oils with specifications from SA to SH are typically suitable for engines manufactured before 1995. However, it's important to note that higher specification oils can be used in place of lower ones. For example, an oil with specification SQ can be used for engines requiring API SP, SN, SM, SL, and SJ.

On the left are all the API categories for Petrol, primarily for passenger cars, as the majority of vehicles in the US run on Petrol (also known as Gasoline) rather than Diesel.

When selecting the right oil for your vehicle, consider its year of manufacture. Modern oils may not be compatible with older engine designs. Specifications from SA to SH are outdated and meant for engines made in 1995 and earlier. As explained earlier, newer specifications have higher letters and replace older ones. API SQ to SJ are for newer cars, while API SH to SA are for older ones.

For instance, If you own a car from 1987 requiring an API SF oil and only have oils with API SH and SL available, the oil with SH level would be most suitable. Alternatively, a car from 2003 requiring API SL can safely use oils with specifications SJ, SM, SN, or SQ.