All About Motor Oil

All About Motor Oil

What it’s made of, how each type works, how to check it, and when to change it.

Have you ever wondered what motor oil is made of? Or how it functions in your car? Maybe you worry about using the right type and weight for your vehicle, or how to know when to change your oil. This article will cover these topics in depth to provide you with the insight and knowledge necessary to make an informed decision when receiving regular maintenance for your vehicle.

What is it made of?

Conventional, standard oil is made up of a hydrocarbon base derived from natural gas or crude oil. It is also referred to as “mineral oil” when used for automotive applications. This base oil, when used alone, is insufficient to provide protection within the engine of a high-performance vehicle. However, when used in older vehicles that are not expected to be subjected to rigorous demands while driving, mineral oil alone provides acceptable protection and lubrication.

In order to provide protection for the nuanced facets of engine lubrication, additives have been engineered at the molecular level to provide solutions for various motor needs. Some types of available additives include dispersants, detergents, anti-wear additives, friction modifiers, antioxidants, anti-foam agents, corrosion inhibitors, viscosity index improvers, and pour point depressants. These can be added to mineral oil to create a mixture of the two substances, and is typically referred to as a “synthetic blend.” These blends are usually 70%-90% mineral oil and 10%-30% additives by volume.

Some types of motor oil are fully synthetic, meaning each component was designed for a specific function within the engine of a vehicle. These types of oil are conceived at the molecular level and then manufactured en masse. The additives that are combined to produce fully synthetic motor oil are composed of various substances, including both organic and inorganic complexes, such as fatty acids and phosphates, or artificial metallic compounds.

What types are there?

As briefly discussed above, motor oil is available in three forms: standard oil, synthetic blend, and full synthetic. By nature, each of these forms are created differently, but there are also differences between brands or even within one brand that provides more than one product composition for a given type. For example, one brand may carry four different fully synthetic products that serve different purposes in the maintenance and performance of a vehicle.

Regardless of the type of oil used, all motor oil has a specific weight. The weight of the motor oil refers to the viscosity of the oil, or its ability to flow throughout the engine and engine components. Different engines require different weights due to manufacturer specifications and/or engine needs, such as protection for high-performance usage.

As an example, oil viscosities are written as 5W-30 or 10W-40. This reflects the Viscosity Index of the oil, which is the basis for the formulation of weights. The number before the “W” indicates how viscous the oil is in cold weather. The “W” indeed stands for “Winter,” and is indicative of the point at which the oil is affected by the cold. The lower the number, the longer the oil will stay viscous and flowing freely before thickening and taking on sludge-like properties. In our given example, 5W-30 would function longer if the temperature dropped (approximately -31°F) than the 10W-40, which would begin to congeal at approximately -22°F. The number after the “W” represents the ability of the oil to function in hot weather. The higher the number, the thicker the viscosity at a specified temperature.

How do they work?

The general purpose of oil in a vehicle is to lubricate the engine parts, reduce friction, and keep the engine clean, cool, and protected. Synthetic additives have specific functions, such as suspending dirt and grime within the oil, lubricating moving parts, preventing deposits on internal engine components, and enhancing fuel efficiency.

Specific types of additives and their functions include:

o Dispersants that prevent sludge build-up

o Detergents protect high-temperature surfaces from deposits

o Antioxidants prevent oxidation, which can accelerate the formation of sludge and thickening of the oil

o Anti-foam agents prevent the formation of foam in the oil, which inhibits the ability of the oil to properly cool the engine due to less oil being present as it exists only around the air bubbles

o Rust & corrosion inhibitors do exactly as their names imply and prevent rust and corrosion of internal components

o Viscosity Index improvers maintain the ability of the oil to resist viscosity changes when the temperature changes

Other types of additives exist, each with its own specific function. Synthetic blend motor oil will consist of mineral oil plus some additives, while full synthetic motor oil is a purely manufactured concoction of various additives.

How long do they last?

The number of miles that an engine can run before the oil needs to be changed is dependent upon the type of oil used. A general rule of thumb is as follows:

o Conventional oil should be changed every 3,000 miles

o Synthetic blends should be changed every 5,000 miles

o Full synthetic oil should be changed every 7,000 miles

For diesel applications:

o Conventional oil should be changed every 3-5,000 miles

o Full synthetic oil should be changed every 7-10,000 miles

Over the life of the oil, the reduced integrity and inability to flow can lead to failure of the oil to properly lubricate vital engine components. This can lead to accelerated deterioration of critical motor parts and functions, which can necessitate further mechanical repairs in addition to the regular oil change. Additionally, the oil itself can become corrosive to the engine surfaces and components if not regularly changed. The corrosive property of aged oil has the ability to disintegrate non-metal gaskets and seals, causing them to seep and eventually leak.

How do I check it?

The current level of oil in your vehicle can be determined via assessment of the dipstick. This is the metal rod, typically with a plastic tip or ring, that protrudes from the top side of the engine and extends into the oil reservoir. The end of the dipstick that remains in the reservoir is etched with markings that identify the required oil level.

If the amount of oil on the dipstick falls within the specified range, and is not too dirty, it will sufficiently perform its functions within the engine. As the oil moves through the motor during vehicle usage, it collects dirt and debris and suspends them within the oil to prevent build-up on engine surfaces. This is good for the motor; however, it inherently requires that the oil be changed regularly. If you require an oil change, you may contact Mike’s Auto Repair located in Westwood, CA, at (530) 776-9478, via Facebook, or at their website.