with prices starting from as low as R300 per litre.
Synthetic oils are based on mineral oils and contain compounds of similar density and structure, but they are highly refined, and therefore offer better lubrication. Synthetic oil is recommended for high-performance engines and are relatively expensive, with prices starting from R1,000 per litre. However, they do have benefits over mineral oils.
Blended or semi-synthetic oil, as the name suggests, is a mix of the above two. Generally speaking, the mix will contain more mineral oil than synthetic, and it’s worth checking, because blended oils are often classified as synthetic oil by manufacturers. Prices of blended oils, on average, start from R450 per litre.
Grades & classifications
Now that you know what kinds of oils are available, you also need to know which grade and service classification suits the engine in your car. These are nothing but a description of the oil’s fluid properties and performance capabilities.
Before we go ahead, we have to understand what viscosity is. In simple terms, it’s the thickness of a fluid. For example, water is less viscous than Fevicol. And the grade of the oil refers to its viscosity at normal operating temperatures.
For oils, a rating by an organisation called the Society of Automotive Engineers (SAE) is used, and is represented by numbers like 0, 5, 10, 15, going on to 60. The higher the number, the greater the viscosity. Now, here too, temperature has a part to play. The majority of an engine’s wear and tear happens when you start the car, because the engine is at its coldest. However, once the engine is warmed up and spinning faster, you need oil with different properties. Previously, you could only get ‘single-grade’ oils, with a constant viscosity across all operating temperatures. These days, however, most oils are of the ‘multi-grade’ variety. These exhibit varying viscosity at varying temperatures and have a two-number rating, such as ‘10W40’.
The ‘W’ in the rating stands for Winter, and this refers to its cold-running viscosity rating. In this example, the oil will have a viscosity of a 10-grade oil at lower temperatures and a 40-grade