Why do I need to know so much about engine oil?

Walk into any auto-parts shop, and you can easily see that there are a great many different engine oils out there. There are countless oil manufacturers, and each of them offers a whole range of grades for different engines, conditions, and even seasons. How is an ordinary car owner supposed to make sense of all this, and does he even need to bother?

Unfortunately, yes. The thing is, an engine oil's label won't tell you whether it's compatible with your particular engine, the way it often does with other parts. That's mainly because even different engines within a single model from a single manufacturer are designed for engine oils with different properties, and listing every compatible engine on the oil's label is simply impossible. What's more, a single engine often allows for several types of engine oil at once, which complicates things even further.

Without a doubt, the simplest option is to always buy engine oil from your car manufacturer's official dealership, on the theory that they surely know which oil suits the engines that manufacturer builds. That's not just the simplest option, but probably the most correct one too, though it's far from the cheapest, and not every car owner even has such an official dealership in or near their city.

What's more, using genuine engine oil bought from an official dealer of the carmaker mostly makes sense for new or nearly new cars. For engines with real mileage on them, the "officials" often don't have much to offer.