With complete service packages offered when you buy a new car, you rarely need to make a choice when it comes to engine oils. Buy a brand-new Perodua Axia and Perodua will make sure the car uses the brand’s namesake oil during the warranty period. The same goes for other brands which may officially use Petronas or Shell lubricants at their service centres.
Even when you go to your local workshop, they are usually already official distributors of certain engine oil brands. Deciding on what engine oil you should use then, is usually a matter of concern for owners of cars beyond their warranty periods, owners of second-hand cars, or just people who generally care about their cars.
Q: So, how do you choose the right engine oil for your car?
A: It’s simple. Just refer to the user’s manual of your car and buy genuine engine oil. There’s always a free PDF somewhere on the internet.
Unless your car has a hipster engine like the Mazda RX-8, the general rule is to follow the user instruction manual on what engine oil grade you should use.
Everything else from here is just an elaboration on the topic.
Q: What is 10W-40, 10W-30, or 5W-40?
A: Before we get to the “W”, let’s talk about the numbers. The numbers are grades of viscosity. The higher the number, the more viscous the engine oil is. If you’re wondering what viscosity is, well, paint is more viscous than water.
Paint takes longer to pour. That’s it.
##W-30 is more viscous than ##W-20, and ##W-40 is more viscous than ##W-30.
Q: What does “W” stand for?
A: Winter. Seriously.
Q: Is viscosity important?
A: Yes. Viscosity degradation is what determines your service interval.
In cold conditions, 15W-## is more viscous than 10W-##. 10W-## is more viscous than 5W-##.
Q: Does the “W” number matter in Malaysia?
A: No. The “W” number is an indicator of how well the engine oil works in really cold temperatures.
Q: Is 10W-40 worse than 10W-30 then?
A: No. The viscosity of the engine oil you should use depends on the clearance levels of your engine. Different engines have different clearance levels and hence, suit different engine oil grades.
Q: What is mineral, semi-synthetic and fully-synthetic oil?
A: They are the types of engine oil you can buy of the shelf. Semi-Synthetic Oil is generally a blend of fully-synthetic and mineral. Semi-Synthetic Oil is often marketed as Synthetic Technology Oil.
Q: What is the difference between these three types of engine oils?
A: Well, they are all mineral oils. Just that fully-synthetic oil is a more refined version of the normal mineral oil. Turning mineral oil into synthetic oil is an expensive process.
While synthetic rubber is artificial rubber, synthetic oil IS NOT ARTIFICIAL OIL.
Q: What advantages do synthetic oils offer then?
A: Firstly, synthetic oils offer more consistent oil molecule size. The illustration by lubrita is a perfect representation.
More benefits of synthetic oils are:
Better low- and high-temperature performance.
Possibility longer service interval
Improved fuel economy (in certain engine configurations)
Increased horsepower and torque.
You just needed to read increased horsepower and improved fuel economy to convince you to go synthetic. There are even more benefits of synthetic oil but you’d have to increase your nerd levels before we discuss that.
Q: “So I’m good to buy this RM70 engine oil from Lazada then?”
A: Well, you can do anything you want with your life, but you have to bear the consequences. Counterfeit products are dangerous and counterfeit engine oil could risk the well-being of your engine.
Be nice to your car and feed it with genuine oil of the recommended grade.
Previously an engineer in an automotive manufacturing company and a highway concessionaire. A part-time research student on biofuels and diesel engines. Obsessed with vehicle electrification and the future of transportation.