Engine Oil Fundamentals – Part 2: Adding the Magic with Additives

In the second part of a three-part introductory primer on engine lubricants, we take a closer look at their second fundamental component – additives. We dive into what are the different types of additives, why they’re important, and why we need to balance the amount of additives in lubricant formulation.

When we try to understand the fundamental components of lubricants, we need to talk about their base (pun unintended) components – base oil + additives. In part 1 of our series, we discussed the basics of base oils to explain their importance in determining the final lubricant properties.

In this article, we look at the second component of additives – and how they add different properties/characteristics to the final lubricant.

Impact of Basestocks and Additives on Lubricant Properties

The final properties of the lubricant depends on the characteristics of their base components. Below is a table summarizing if additives (and base stocks) have a primary or secondary impact on the final lubricant properties.

Chart

Balancing Additives is Critical

equation: Base oil + Additives = Engine oil

Additives are used to improve the original properties of base oils and enhance their performance. They enhance the oil’s ability to lubricate and protect, and also help extend the life of the oil.

However, more additives within the formulation is not necessarily better. The key is the balance of additives in the finished blend. For example, ExxonMobil scientists carefully select additives that are compatible with each other and with the base oil to formulate engine oils like Mobil Delvac.

Additives can be grouped into three main types as seen below – Performance Modifiers, Lubricant Protectors, and Surface Protectors:

What about After Market Additives?

Do not add anything to a formulated oil!

Blindly adding more additives in the mix usually isn’t better. Typically, an overdose of one type of additive to enhance a property (e.g. anti-wear, friction modifier, viscosity improver) will upset the balance of additive chemical properties in the finished engine oil.

Some of you may have heard about “top treats” or even considered using them. These are concentrated additives, and when added to an approved, fully formulated oil, they change the formulation and invalidate the approvals.

Their use can void the warranty; no major engine manufacturers recommend or endorse after market additives. Engine oils are manufactured to meet the warranty standard with the approved additive system. And OEM warranties require engine oils that are fully approved within the latest standards.

If you have any questions, always consult your lubricant supplier.

In the next and final part of our primer on engine oils, we’ll talk about different lubricant specifications and classifications, as well as what are SAE viscosity specifications.

Do you have any questions about the role of additives in engine oil? Share them with us in the comments below, or hit “Like” on the toolbar on the right if you found this refresher useful!

Anonymous
  • Hello there,

    As you know we are moving to the following trends in engine oil development:

    Lower HTHS for fuel economy

    Lower ash levels for catalysts and filters protection - this is main contributor why you see less and less P and S elements. These are cheap additives, but they contrbute to sulphated ash levels. 

    There is another factor - Low Speed Pre Ignition (LSPI) in direct injection gasoline engines. That's why you will see less and less Calcium in new oils for gasoline engines and adjusted levels of Magnesium.

  • Mikhail, thanks for share these information.

    I would like that you talk about of additives level for Phosphorus, Zinc, Calcium, Magnesium, Molybdenum. What is the main function for example of phosphorus (anti wear), Magnesium and Calcium (detergents)?, etc. Also, what happen, if the engine oil has too much additives levels? We know that the new specifications (API) have reduced certains elements, for example, phosphurus and zinc, why? what is their influence on performance of engine oil?

    I’ll appreciate any comments. Thanks so much

  • Mikhail, thanks for share these information. I would like that you talk about of additives level for Phosphorus, Zinc, Calcium, Magnesium, Molybdenum. What is the main function for example of phosphorus (anti wear), Magnesium and Calcium (detergents)?, etc. Also, what happen, if the engine oil has too much additives levels? We know that the new specifications (API) have reduced certains elements, for example, phosphurus and zinc, why? what is their influence on performance of engine oil?

  • Great information Thanks for sharing! Do have one question,I have always thought that a demulsibility additive was not part of the make up of automotive lubricants mainly due to the issue of the oil pump suction in oil sump picking up a slug of water and sending it to the engine at startup.