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Selecting the right engine oil can be challenging for most of us. Multiple types, different numbers, letters, variant grades, and viscosity are available in the market. 

So, how to select the right one? Will it be ideal for the current weather conditions? How long will it last before a change is recommended? Is it ok to mix them up?

Seems like quite a challenging decision to make!  That’s why we usually leave it to the mechanic to recommend one for us.

But not to worry, in this article, we will guide you to pick the right oil for your car. 

Understanding Engine Oil

Total Lubricants: Inside the Engine

Every engine needs oil to run properly. In fact, it is an essential element since engines are exposed to harsh conditions, extreme temperatures, high pressure, tremendous heat friction, sludge accumulation, and more.

As critical as it may be, it is important to choose the right oil as it can have various effects on the longevity of your engine. It doesn’t only increase the life of it, it also allows it to run much more efficiently. This can increase your fuel efficiency & lower your average fuel spendings.
Let's say you are in a workshop, you will definitely see numerous products with a wide variety of features and symbols that might confuse you. So, which one should you pick out? 

Different engines require different oils to function and operate normally. It is always recommended to start your search by checking the owner’s manual of the car as it will recommend the right oil based on some parameters of your car. 

In addition to that, many engine oil advising tools are available online, where simply you enter your car make, model, specifications, and year and it will give you some recommendation for your car.

What are the Engine Oil Types?

Not all engine oils are the same. It is important to choose an oil that is suited to your car and local climate conditions to enjoy all its benefits. There are four types of oil:


  • Mineral Oil:

Mineral oil, also known as “conventional oil”, is the most basic & affordable type of engine oils, obtained from refined petroleum crude oil. Commonly they are used for a large majority of everyday vehicles.  

Mineral oil is thicker than other oil types which causes a slower flow rate that results in increased fuel consumption. 

Mineral engine oils are less resistant to high temperatures and oxidation compared to synthetic engine oils, and have higher liquid points, which makes them favorable for winter conditions and extremely low temperatures.

And because of that, mineral oils require frequent oil changes, after every 5,000 to 10,000 kilometers or every four months.


  • Synthetic Oil:

Synthetic oil is a product of complex chemical transformations that are performed either directly on drilled crude petroleum or using preselected molecules. It undergoes more sophisticated modification.

They hold many advantages:

  • Synthetics don't break down or sludge up as fast as ordinary mineral-based oils do. In other words, it has less deposit formation which leads to cleaner engines.
  • Better engine protection that increases its health & life span
  • Stable flow performance & viscosity during extreme temperatures
  • Fuel consumption optimization

And not to forget, one of its main perks is that it requires less frequent oil changes. Synthetic oil can last between 10,000 to 25,000 kilometers or every six months before its next change. 

However, the main disadvantage of synthetic oils that makes the least favorite to people is that they are slightly more expensive.  


  • Semi-Synthetic Oil: 

Semi-Synthetic oil is also known as synthetic blends & as hybrid lubricants; is a mixture of mineral and synthetic oils that reserves the best features of both oils. 

Semi-synthetic oils can be the best choice for engines that encounter heavy loads caused by intensive usage.

Often a 7,500 to 15,000 kilometers oil change is the recommended mileage between oil changes or every six months.

Semi-synthetic oil is more of a wallet-friendly than fully synthetic oil as they are of a lower cost. While getting some benefits of the fully-synthetic oil, it can be your next best choice.


  • High-Mileage oil:

This oil has a different combination of additives that might be a little better suited to engines with a lot of wear, tear, and miles on them.

High-mileage oil is designed mainly for older engines -those with more than 100,000 kilometers of use-  that might encounter some flexibility and leak problems. It has certain ingredients that can fix these problems, such as conditioners, antioxidants, and seal sweats. 

Because of that, these kinds of engines require shorter change intervals estimated as 5,000 kilometers or three months. 

Did you Know?

Have you ever looked at the engine oil bottle and wondered what all these numbers and letters stand for? 

There are many different ways in describing motor oils, each refers to a certain standard of classification. 

Knowing such information allows you to understand:

  • The design of motor oil type for your car engine (diesel or petrol)

  •  The lubricant performance level.

  • And whether it meets your cars’ manufacture recommendations.

​​​​​Here are the three standards used for describing the oils:

  • The SAE standard

Society of Automotive Engineers (SAE) standard developed a scale for engine oil grades that describes the degree of oil viscosity. 

You can see its indication on the front of the container as the xxW-yy index format.


  • The ACEA standard

The standard of the European Automobile Manufacturers' Association, is a quality standard that uses letters and numbers classification schemes. 

The letter indicates engine type:

  • A-petrol engines

  • B-diesel engines

  • C-light engines

  • D-commercial vehicles and trucks.

And the number indicates the specific level of oil performance. The higher the number is, the greater it performs. 

The 2016 ACEA guidelines define: 

  • 3 category combinations for petrol and diesel engines: A3/B3, A3/B4, A5/B5. 

  • 5 categories for vehicles with a pollution control device: C1, C2, C3, C4, C5. 

  • & 4 categories for commercial vehicles and trucks E4, E6, E7, E9, of which two are for vehicles with a pollution control device: E6 and E9.


  • The API standard:

The American Petroleum Institute Standard classifies the product according to several criteria: 

  • Dispersive and detergent power

  • And protection against wear, oxidation, and corrosion. 

It uses a two-letter standard:

  • The first letter is either S - for gasoline engines or C - for diesel engines. 

  • The second letter indicates the performance of the oil. The further along the alphabet letter is the higher quality of the motor oil. 

As an example, an SH oil will have lower performance than an SN oil. 

Does the Viscosity of Motor Oil Matter?

Yes, viscosity does matter!

Viscosity simply means the thickness of oil and how easily it flows inside the engine at different temperature extremes. 

Oil with a low viscosity grade will flow faster in cold weather as it will be more fluid. And vice versa, Oil with a high viscosity grade has a thicker flow that helps maintain the oil pressure at high temperatures.

It is ideal to have an oil that can withstand the hottest temperatures in your region while still being able to flow & perform during the coldest weather.

So, What Do Those Numbers & Letters Actually Mean?

The engine oil grade consists of 3 characters - the xxW-yy format. Let's start by explaining what each means:


  • The letter W that you always see on the oil bottle stands for the word Winter, ie. how oil will perform in cold weather. 
  • The number before the W (i.e. the xx) refers to the level of oil flow in cold temperature. The smaller the number is the thinner & better flow it will be. 
  • The number that comes next (i.e. the yy) refers to the flow of oil at high temperatures. The higher this number is the thicker & better flow it will have. 

As an example: a 5W-30 motor oil has a viscosity of 5 in low temperatures and viscosity of 30 at higher temperatures. Versus the 10W-40 motor oil that has a viscosity of 10 in low temperatures and viscosity of 40 at higher temperatures.

To Mix Oils or not to Mix, That's the Question!

One question that keeps knocking our minds is that if it's ok to mix up different types of oils or not. Answering this question may be very helpful, especially if you need an urgent top-up of oil and much choice is not available.

Well, mixing up oils may not kill your engine, but continue reading this article and then make your final decision. 

If it ever occurred to your mind if mixing up different brands of oil is ok, you should think again. Each brand has developed certain chemical components for its product, mixing up these components may result in unneeded reactions, and success is not guaranteed. 

That's why it's not recommended to mix them up.

Are you now thinking that mixing up different oil types is ok? Well, no. Mineral oils and Synthetic oils are incompatible in viscosity grades. This incompatibility can cause many problems, such as a reduction of effective additives and an increase in oil thickness which eventually affects the performance of the engine. 

After all, mixing up oils is not your best choice all the time, so think twice before you do it. 

So Remember,

taking care of the engine will increase the lifespan of your car

When your car is due for an engine oil change, remember the following:

  • Know your car engine model:

Different engines require different oils to perform ideally. When in doubt, start your search by checking your cars’ owners manual, check the available engine oil advising tool online, or get the advice of a professional.

  • Mineral or Synthetic:

Each type has its pros and cons, so knowing what type of engine is yours is very helpful in this matter. Mineral oil for instance is affordable but doesn't last long. Synthetic on the other hand perfect for protecting your engine but it's rather expensive. 

  • Choose the typical Viscosity grade:

Remember the numbers on the bottle. The number written before the W (Winter) indicates the oil viscosity grade for cold temperatures, as the number after the W indicates the oil viscosity grade for hot temperatures. 

  • Mixing Up Oils?

And as mentioned earlier,  mixing up oils is not your best choice all the time, as doing so might result in harmful problems.