Motor Oil vs. Engine Oil (6 Facts You Should Know)

ByChris Moore
engine oil

So, the mileage on my car’s odometer has hit the mark that ‘requires’ the routine engine service. As I drive to the mechanic, I grapple with the question, ‘what should be changed?’ Is it the motor oil or engine oil? What I am sure of is that oil must be changed!

A simple search reveals that more and more people, just like me, get confused about which term to use, especially when they need to be specific on what type of oil should be changed. 

Is it motor oil or engine oil? Confusing, right?

Let us delve deeper into this to get the answer.

The terms ‘motor oil’ and ‘engine oil’ are used interchangeably to refer to any substance with base oil laced with additives such as viscosity improvers, antiwear additives, dispersants, and detergents.  While we may be attracted to the idea of differentiating the terms’ motor’ and ‘engine,’ it suffices to note that these terms are used interchangeably nowadays, and this means that motor oil and engine oil are the same products on the market.

Can I Put Motor Oil in My Engine?

Technically and practically, YES. Motor oil and engine oil products are the same, and manufacturers label them interchangeably.

Choosing between motor oil and engine oil had been confusing initially but later on, I realized that it’s the same thing. What I have learned is that caution must be taken so that you only use the type of engine oil stated by the car manufacturer.  

How Many Types of Engine Oil Are There?

Immediately the engine cranks up and starts running, the combustion process produces by-products that can contaminate the engine oil. If these by-products aren’t cleaned, they accumulate and form oil sludge in areas of the engine that can be stubborn to remove.

When we don’t regularly change the engine oil or use low-quality ones, this sludge forms and affects engine performance, efficacy, and fuel consumption.

Here, we have different types of engine oil that can be used for the car.

Synthetic Oil

Simply put, synthetic oil is artificially derived from chemical compounds modified from Petroleum compounds and not the whole crude oil. Besides, this oil can also be synthesized from other raw materials.

While it’s true that fully synthetic oil is derived from the same material as mineral oil, it’s highly refined, distilled, and purified to remove impurities and to align individual molecules to meet the specific demands of modern engines.

Synthetic oil like Mobil 1 Advanced Fuel Economy is believed to be hard on seals thereby causing oil leaks.

But why the leaks?

Older engines have seals, gaskets, and other vital components that are usually not as tight as those found in the newer engine models. Conventional oil accumulates sludge in these components with the benefit of sealing those gaps.

With synthetic oil finer molecules and high cleaning properties, this oil cleans off the sludges, exposing the already existing gaps and cracks hence the oil leakages experienced.

Generally speaking, synthetic oil lacks impurities, and its molecules are shaped uniformly compared to mineral oil. With high-performance additives, this type of oil performs better, whether in low or high temperatures.

Pros

  • Low viscosity leads to high engine efficiency as well as increased fuel economy
  • High oxidation resistance means less sludge formed and reduced engine wear
  • Less frequent oil changes leads to reduced expenses on engine oil
  • Excellent flow even at low temperatures improving overall fuel economy

Cons

  • Slightly pricey
  • Likelihood of additive stratification in cold weather which can lead to their complete separation from the oil

Mineral Oil

Mineral oil is derived from naturally occurring crude oil, refined to produce gasoline and other petroleum products. Through this refining process, wax and other impurities are removed, presenting it in different quality levels and viscosity grades.   

Usually, it comes as a transparent oil made of cycloalkanes and alkanes.

This engine oil is fit for engines with simple designs, and we find it also appropriate for drivers with a light foot and with varying driving skills.

Pros

  • They are affordable
  • Easily available
  • Ideal for older engines

Cons

  • Flows slowly in the engine leading to higher fuel consumption
  • Requires frequent oil change, which leads to high costs
  • Impacts negatively on the engine performance

Derived from a mixture of conventional mineral oil and synthetic oil, this engine oil contains additives that offer oxidation resistance while providing excellent engine performance in low temperatures.

Semi-Synthetic Oil

Semi-synthetic oil such as Yamalube Performance Semi-Synthetic 10W-50 contains mineral oil and fully synthetic oil properties, offering a middle ground that is affordable and common on the market.

Other than that, semi-synthetic oils have seal conditioners meant to prevent oil leakages in engines that have clocked over 75,000 miles; antioxidants that work against oil breakdown; and friction modifiers guard the engine against wear and tear, guaranteeing the engine long life.

The primary purpose of getting this synthetic blend is to benefit from the mineral oil capability of holding additives in suspension while enjoying synthetic oil’s scrubbing capability and oxidative stability.

Pros

  • It offers better engine protection than mineral oil
  • It’s more affordable than fully synthetic oil
  • It has high performance power compared to mineral oil
  • It resists oxidation
  • Works well under low temperatures

Cons

  • It doesn’t perform as high as fully synthetic oil

High-Mileage Oil

Most high-mileage oils are formulated for vehicles whose mileage has clocked 75,000 miles and above. They have seal enhancers and additives that prevent both internal and external leakages.

Here, we seek to understand how this happens.

The special additives and seal enhancers in high mileage oils make the seals, o-rings, and gaskets to swell. Once this happens, the gaps in those components are blocked, preventing leakages that could occur. The net effect of this is less fuel consumption, leading to low fuel costs.

Additionally, high mileage oils contain detergents designed to scrub sludge from the engine, leaving a clean and efficient engine.

Even with these praises, we don’t recommend high mileage oil as a ‘silver bullet’ for your engine’s mechanical wear. Have regular engine checks to avoid having a stalled car!

We find High mileage engine oils such as  Pennzoil 5 quart to contain additives that help prevent the accumulation of sludge and other deposits in the engine.

When it comes to how frequently you should change the oil in your high mileage engine, the general rule is to consider the engine’s condition. 

Of course, a well-maintained engine can support longer oil change intervals, while an engine that’s burning oil can’t support longer oil change intervals.

Pros

  • Reduces oil leaks by conditioning engine seals which may have degraded over time
  • Cleans sludge formed by other oils
  • Stops oil loss that results from burn-off
  • Improves fuel efficiency
  • Minimizes engine wear and tear

Cons

  • It’s a bit pricey
  • Once you start using it, switching to other engine oils will cause more leakages

As a general rule of thumb, we highly recommend following your car’s manual to determine the correct type of engine oil to use, the viscosity grade, and the oil change intervals.

Why Is Motor Oil Used?

To run correctly, every machine needs lubrication to prevent wear and tear. This makes motor oil an integral part of every machine or engine.

Let us look at the different roles that motor oil plays.

  • Lubrication

Lubrication is the primary role that motor oil plays. Most engine parts and systems are in constant friction, and if not lubricated well, they wear off, leading to high maintenance costs.

  • Cooling

Engine temperature usually rises as combustion and friction between the engine parts and systems occur. To cool the engine, motor oil is designed to trap, transfer, and release this heat via the lubrication circuit. It does this while complementing the engine coolant, which only cools specific engine parts.

  • Cleaning 

While this may not be commonly known, motor oil’s cleaning capability is crucial in maintaining the engine’s good health.  Minute deposits of combustion residue and dust accumulate as the engine runs and needs to be cleaned out. Only motor oil can perform this task. If left to accumulate, these deposits can eventually clog the engine and reduce its efficiency.

  • Corrosion Protection

Generally, motor oil contains oxidation and corrosion inhibitors.  It should be noted that fuel combustion produces corrosive acids, which are detrimental to all engine parts.

However, the good news is that modern motor oils contain additives that counter these acids and subsequently neutralize their corrosive powers.

Even with this power, motor oil should be changed regularly because exposure to oxygen leads to oxidation, which renders it ineffective.

  • Sealing

Motor oil promotes the sealing of pistons and cylinders in the engine. This oil does this by forming protective layers between the different components, blocking the clearances that may appear.