What is Motor Oil?

Historically, motor oil was just a mixture of base oil and additives used to lubricate engine parts, reduce friction, clean, cool, and protect the engine.

However, modern, synthetic motor oils are a complex mixtures of base oils and additive components designed to perform a variety of tasks: separating and lubricating moving parts, reducing engine wear, helping to prevent deposits from forming on internal engine components, removing and suspending dirt and contaminants in the oil until these contaminants can be removed at the next oil change, cooling engine parts, enhancing engine fuel economy, providing protection over a wide temperature range, operating hydraulics in variable valve timing, and even helping to protect the emissions system. In other words, modern synthetic motor oil does a lot more than just lubricate.

Engine oil is comprised of two basic components—base oils and additives. The base oils constitute 70 to 90 percent of the total, while additives round out the remaining 10 to 30 percent. These additives include dispersants, detergents, anti-wear additives, friction modifiers, antioxidants, anti-foam additives, and corrosion inhibitors, viscosity index improvers, pour point depressants, and more.

Why is a Motor Oil’s Ability To Clean Important?

Every time your engine is running, by-products from combustion contaminate your engine oil. If the contaminants build up in the oil, they can settle and create sludge and deposits in the engine. Using low quality motor oil, neglecting to change your oil, and maintenance issues can also lead to sludge forming in your engine. If your engine components and oil passages are dirty, your vehicle performance, efficiency, and fuel economy may suffer. Deposits also trap heat inside your engine like an insulating blanket. This is why it is important to use a motor oil like Pennzoil Platinum® Full Synthetic motor oil with PurePlus™ Technology that helps keep engines cleaner than any leading synthetic motor oil.1

1Based on Sequence VG sludge test with SAE 5W-30

What are Dispersants?

A dispersant helps your engine’s performance by helping to keep sludge from forming on internal engine parts by suspending contaminants in the oil until they can be safely removed at the next oil change.

What are Detergents?

Detergents operate on high-temperature surfaces, such as the piston-ring area and the piston under-crown, helping to prevent deposits. These detergents get consumed over the life of your oil change.

Why are Anti-Wear Additives Important?

High pressure points, like between the camshaft lobe and its follower, can reach over 200,000 pounds per square inch of pressure! The advanced anti-wear additives in Pennzoil® Synthetics, like ZDDP or “zinc,” form a protective layer that is thinner than a strand of human hair, yet able to absorb impact at high pressure points inside your engine. Antiwear additives operate under high temperatures and high load conditions, particularly protecting camshaft lobes, lifters, piston rings and cylinder walls. Antiwear additives coat these surfaces in a “sacrificial layer” or film, which is consumed as it protects. Without this “sacrificial layer,” metal-to-metal contact would occur. Like detergents, antiwear additives also get consumed over the life of your oil change. This is another reason you should always change your oil at recommended intervals.

What Do Friction Modifiers Do?

It's pretty straightforward—they reduce friction under high loads and high temperatures, helping to maintain peak efficiency and fuel economy. The effectiveness of these additives diminishes over time as the oil ages.

The Reason Your Oil Needs Antioxidants

Oxidation results from exposure of the oil to oxygen at high temperatures. It’s not a good thing. The results of such exposure can accelerate the breakdown of the oil and contribute to oil thickening, sludge and deposits. Antioxidants help slow oxidation in the oil to help keep engines running clean.

Three Reasons Your Oil Needs Anti-Foam Additives

Foam-causing air bubbles create a variety of problems in oil. They make oil harder to pump to vital engine parts, reduce the oil’s lubrication effectiveness, and inhibit the oil’s ability to help keep the engine cool. A foamed-up oil can result in serious engine damage. An anti-foam additive helps prevent these problems, specifically at high temperatures.

How Rust and Corrosion Inhibitors Benefit Your Engine

It might sound strange, but internal engine parts can be subject to rust and corrosion. Rust and corrosion inhibitors coat metal surfaces, protecting against these hazards. Rust inhibitors help protect against the reaction of water on metals. Corrosion inhibitors help protect against the reaction of acids on metal.

Understanding the Need for Viscosity Index Improvers

The viscosity index measures an oil’s ability to resist changes in viscosity as temperature changes. Viscosity index improvers utilize polymer additives to help maintain oil viscosity over a wide range of temperatures. The use of viscosity index improvers allows the formulation of multi-grade engine oils, such as SAE 0W-40 and SAE 5W-30.

Pour-Point Depressants are Important. Why?

Pour point depressants help motor oil flow at extremely low temperatures. Flow is important in cold engines as oils that are difficult to pump at cold temperatures require additional energy to circulate. This results in added stress on the engine and decreased efficiency.