Which Engine Oil is Best for My Car?

How can you decide which engine oil is the best for your car? Given the choices available, this can seem like quite a difficult question. But here’s a simple guide.
Let’s start with engine oil grades (and what all those numbers and letters mean).

Understanding engine oil grades

Engine oils for cars have a designation in this format: XXwYY. For example, 5w30 or 10w40. The letter ‘w’ stands for ‘winter’ and the numbers on either side represent the oil’s viscosity – in other words, how easily the liquid can move or be poured at different temperatures. The first number represents the viscosity at low temperatures, while the one after the ‘w’ represents viscosity at high temperatures. Both are important: the first one is for helping your engine start without clogging it up, and the second one is for helping it function properly at very high internal temperatures.

How does engine oil viscosity affect my car?

In layman’s terms, in cold climates, you need a lower number before the ‘w’. In a warm climate, a higher number is also fine.

As for the number after the ‘w’, this represents how quickly the oil will thin out at high temperatures. If you have a car that has an older engine or takes heavy loads, then you need a higher number after the ‘w’.

Some common car engine oils

1. 5w30 engine oil: As indicated by the number 5, this oil is more suited for cars in colder climates. This oil flows more easily at lower temperatures, so your engine can start easily and not seize. It’s not required if you live in a place that has warm temperatures through the year.
2. 5w40 engine oil: This oil performs the same as 5w30 at low temperatures. However, this has a 40 grade after the ‘w’. This means it is more resistant to thinning out at high temperatures, thus offering more protection by coating engine parts more efficiently.
3. 10w40 engine oil: This oil is slightly thicker than a 5w when it’s cold outside. This means your engine’s crankshaft needs to work harder to move through this oil. However, if it’s warm, then this oil is fine. Both 5w40 and 10w40 have the same number after the ‘w’, so this means they perform equally well at high temperatures.
4. 20w50 engine oil: This oil has bigger numbers both before and after the ‘w’, so that means it’s best for cars in very hot regions like Africa or the Middle East. The 50 after the ‘w’ also means it’s better suited for vehicles with very heavy loads or older engines that have very high internal operating temperatures.

So that’s it! Now you know the basics of how to choose the best engine oil for your car. If in doubt, head over to your nearest car service center when it’s time for an engine oil change. The mechanics there can give you the best advice.