In choosing which oil to use, there are two basic information that one should know: the viscosity grade which is indicated by the SAE number and the API grade. The SAE grade (Society of Automotive Engineers) shows how thick is the oil at operating temperature, i.e., 210 degrees F. The SAE 50 is thicker than SAE 40 and SAE 40 is thicker than SAE 30. In the Philippines where the temperature is relatively hot, recommended oil is SAE 40 and SAE 50. The right thickness is indicated in your car owner's manual. The SAE 50, SAE 40, SAE 30 are so-called single grade or monograde oils and SAE 10W-40, SAE 20W-50 are called multigrade oils. Under normal conditions, the multigrade oils are more expensive, but they provide better protection for your engine especially if you go to colder areas like Baguio once in a while. The rule of thumb is use whatever is the SAE grade in your car manual. Using thicker than recommended will unnecessarily burden your engine, but using lighter oil on the other hand may shorten your engine life.

The API grade indicates the quality level of the oil. Latest model cars are recommended to use API SM grade which is the highest level at this time. Older cars usually are recommended to use lower API grades like API SL, SF, SG, SE, SC (the lower the alphabetical designation the lower the quality level). Whatever model the car is, it can benefit by using the highest API grade available in the market. However, for those who want good protection for the engine at reasonable cost, the best bet is to stick to the recommendation of the vehicle manual. However, exceeding the API recommendation is a good practice for better engine protection but more costly.