How to Pick the Right Motor Oil for Your Car 7 Pro Tips

How to Pick the Right Motor Oil for Your Car: 7 Pro Tips

Do you remember Castrol’s advertising tagline ‘Liquid Engineering’? I think those words are a good start towards understanding the importance of the oil which you choose. You really should know how to pick the right motor oil for your car.

The word ‘engineering’ usually makes me think about how things are held together. However, with oil it is more a case of holding things apart. When you fire the engine into action the cold-metal pistons and crankcase need to be kept from grinding away at each other. That’s the job of the oil.

The secret to automobile longevity is to know your oil!

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Why is Choosing the Right Motor Oil Important?

How to Pick the Right Motor Oil for Your Car 7 Pro Tips - Oil bottle, funnel and other engine oil related items in a white background

Source: ​Dummies​​​

Maybe you are already getting the idea that I think oil is very important. It helps the engine to start smoothly, it helps the engine to keep running, and it very much affects the longevity of the engine too. I don’t know about you, but it sounds important to me!

From the wide choice of car oil brands and types, the first response to ‘what kind of oil should my car use?’ must be to check with the manufacturer and check the owner’s manual. You might keep in mind that there may be some commercial tie-in influencing the manufacturer’s recommendation.

Types of Motor Oil

Let me see if I can help and explain the various car oil brands and engine oil types. Look at that oil container on the store shelf. Just exactly how many stamps and abbreviations can there be on one piece of packaging? Let me try and make it a little simpler for you. Seems to me there is one place to start, one word which is always present, but probably little understood.

Oil Viscosity

That is what those numbers, 15/25 and 10/40, and their like, are talking about. I thought the chart from Elf was pretty and helpful. It is like Goldilocks’ porridge. Rather than “just right” in terms of temperature, you do not want your oil too thick, or too thin.

However, temperature does come into consideration too. If you have ever left a jar of honey in the refrigerator for very long, you will know that it soon becomes very thick, and will not pour easily. Its viscosity has become very low. Leave honey in the sun, it soon becomes almost watery, such a high viscosity is not good.

How to Pick the Right Motor Oil for Your Car 7 Pro Tips - Oil Viscosity Chart

Source: ​LRDKangan​​​

It is the same with oil. Cold and thick is not good for your engine, nor is hot and thin. Again, you want it just right. The numbers 10-30 represent the viscosity, resistance to flow, tested at 0 and 212 degrees Fahrenheit. With its higher numbers, an oil measured as 20-50 would have better viscosity when cold and when hot.

In respect of oil, it is the most important specification in the manufacturer’s manual, and you just know viscosity is a very technical and complicated topic when there is a whole website devoted to it.

Conventional or Synthetic Oil?

How to Pick the Right Motor Oil for Your Car 7 Pro Tips - Various car oil types bottles showing conventional and synthetic oil types

Source: ​PitCrew​​​

There are broadly two types of oil. There is conventional oil from mineral hydrocarbons which have been drilled for and sucked out of the earth. Then there is synthetic oil which is totally manufactured in factories, by means of chemical processes.

The division is in the claimed quality, and is very noticeable in the price. A compromise is sometimes gained by blending the two types together. There is almost no doubt that engine oil is one of those times when you get what you pay for. Anything you see on the shelves of a U.S. store will do a job. But what you need to ask is will it do the right job in the best way.

Other Elements of Motor Oil

How to Pick the Right Motor Oil for Your Car 7 Pro Tips - Close up of oil being poured

Source: ​GoGirl​​​

Like the ‘NEW! Ingredient X’ which comes in your washing powder, there seem to be lots of things in your oil. Friction modifiers, viscosity-index modifiers, and anti-wear additives are helping the oil to be … well, more slippery and better oil!

Detergents though are about keeping the engine clean on the inside, preventing and removing sticky deposits. Continuing the cleanliness theme, if you think about having a bath in a tub with just bubbles, you might realize that foam inhibitors are a good thing

Motor Oil FAQ

As you might have already realized, this is not a one-size-fits-all situation. I thought the most useful thing might be to give responses to an imaginary Frequently Asked Questions.

How much should I spend?

I do a very high mileage, doesn’t this mean that I should buy the very best oil?

What should I do with a diesel?

My car only goes out only once most weeks, to the supermarket. Any advice?

How does the age of my car affect the choice of oil?

Is synthetic oil worth the money?

What do all those letters and symbols mean?

Any unusual advice?

Any obvious advice?

Any slightly less obvious advice?

Which brand?


There are some more technical aspects which we could talk about, but I hope I’ve encouraged you in the right direction of thinking a little about the importance of the role which oil plays. For my part, I’ve always thought that good quality oil, changed regularly, is the best way I can look after my investment in motor vehicles.

Share the article if you think others might benefit from being encouraged in that direction.
Please take the time to make a comment and tell me what you think!

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