Engine oil: Components, faults, and replacement

Engine oil also called motor oil, is a substance designed to lubricate the inner components of internal combustion engines, it is also present to prevent/protect them against corrosion and keep them cool while in use.

The importance of engine oil in automobiles is very crucial and for this reason, this article aims at equipping us with an intensive knowledge of engine oil. Laying emphasis on the components, faults, and replacement.

Engine oil

Components of an Engine Oil

The motor oil is made from two main elements: base, stock, and additives.

Base Stock: Up to 95 percent of the solution is made up of base stock and is either made from petroleum, synthetic chemicals, or a mixture of the two and also the base stock is responsible for lubricating an engine’s moving parts and removing built-up heat.

Additives: Additives, on the other hand, account for roughly five percent of the oil and it is these chemicals that are responsible for finely controlling oil viscosity and lubricity, and also protecting engine parts against wear and possible tear.

For example, zinc dialkyl dithiophosphate (ZDDP) is a frequently used additive for preventing wear, while magnesium sulphonates help the oil to break down impurities and engine sludge. Learn more about the composition of engine oil here.

How It Works

Want to know how engine oil functions? Watch this to see a simplified description of how it works.

Types Of Engine Oil

Just as car engines differ, the type of motor oil they require differs too. For instance, it can be considered a good idea to use fully synthetic oil for older models of cars. Though it’s more expensive, it will serve better.

Moreover, your car owner’s manual can recommend the type of oil you should invest in. The three main types of oil for most cars are:

Mineral: This is made from refined crude oil, it’s usually the least expensive option, and it should work fine in most vehicles.

Synthetic blend: Made in a laboratory, this type of oil mixes synthetic oil with mineral oil and is generally designed for older, high-performance engines. It’s slightly more expensive than mineral oil, but lasts longer and offers greater lubrication.

Fully synthetic: This type of oil contains no mineral oil and is strong enough to be used in an industrial machine. It has high longevity and tends to be the most expensive option available.Learn more about the types of oil here and find what suits your automobile.

How To Rate Engine Oil

Oils are rated by their grade and viscosity. They can be rated as either be single-grade, with a set viscosity level, or multi-grade in which the oil can act at two different viscosities depending on its temperature.

The latter is the most common today, to cater for vehicles used all year round in various conditions. Lower-ranked oils are thicker than higher-ranked ones, this makes them more suitable for hot environments, and vice versa.

Questions People Ask

When should I change my engine oil?

Your engine oil needs a replacement when it gets dirty. Dirty oil can be harmful to your vehicle as this will disrupt the smooth operation of engine parts in your automobile. It is therefore considered a necessity to occasionally check and replace your motor oil. However, you don’t want to keep replacing a healthy oil so it is also necessary to know the signs that show your oil needs replacement.

What makes my oil dirty?

As time passes, your vehicle's oil filter can collect dirt, junk, and debris. An accumulation of that gunk can cause your engine oil to become dirty. This is absolutely normal but once the oil becomes dirty, it would be very wise to change the oil and possibly the oil filter if necessary.

Why? This is because accumulated dirty oil can harm your car by damaging moving engine parts, decreasing fuel efficiency, or even triggering an engine breakdown.

 Clean VS Dirty Engine Oil

Also, long delays between oil changes and normal engine wear and tear can lead to dirty oil. Driving for long periods of time without an oil filter change can result in dirty oil too. The engine oil and oil filter need to be replaced more often than any other item on your vehicle.

Why should I change my motor oil?

Due to continuous use of your vehicle, the oil in your engine eventually wears out, breaks down, or becomes contaminated with dirt and gunk. As this happens, it becomes less and less effective at absorbing heat and lubricating the important parts of your engine.

If you continue running your vehicle on dirty oil, it would cause its parts to begin to grind together. This causes damage, creates noise, and allows heat to build up, which leads to much bigger issues along the line if not taken care of quickly. Generally, it is recommended that you change your oil every 3,000-5,000 miles.

Knowing a bad or Dirty Engine Oil

One of the most obvious signs that signify a change of oil is color. Is it looking dark and dirty? Then it is bad. A Clean oil has an amber color and is free of dirt, sand or any other contaminants picked up along the road.

It is very common for engine oil to darken over time but when it is dark brown, black, or has any irregularity to its texture, then it’s time to get the engine oil changed and this should be done as soon as possible.

Checking your oil regularly for color and texture changes will help prevent damages to your engine majorly caused by old or dirty oil.Is the checking process new to you? Here is a helpful video guide you through the process.

9 Signs That Shows You Have a Bad Engine Oil

Loud Engine Noises

The most important reason you put engine oil in your car in the first place is to lubricate the engine. This ensures a healthy engine and is why car manufacturers recommend changing your oil every 5,000 miles. In the absence of proper engine oil, metal-to-metal grinding can occur. If this is ignored, this can lead to the engine of your car making loud noises or even outright knocking of your engine. This is a clear sign that your car needs new oil.

Check Engine Light Comes On

The most obvious sign to know when your car is due for an oil change is the oil change or check engine light on the car’s dashboard. If you don’t check your oil level regularly, you perhaps, won’t hear the engine before you see the light.

Any time your oil change light indicator, check engine light, or however your vehicle indicates a need for change, comes on, take care of it immediately. It would be unwise to hold off and hope it goes away on its own.

Addressing the low oil level immediately can help prevent something more serious from occurring and costing you more money down the road. Car models differ, so make sure to check out more specifics for Toyota, Lexus, Honda, and more

Check Engine Light On


Your car engine pump pumps oil to circulate and help lubricate engine parts to prevent friction and eventual wear as it does its job. When your car needs an oil change, the oil is no longer doing its job, and metal to metal friction or grinding can occur.

More friction definitely means more heat and this could be dangerous. Like other gauges on your dashboard, remember to keep an eye out on engine temperature as increased heat is your car telling you it’s working too hard or some cooling system isn’t functioning optimally.

 Engine Temperature Warning Light

Low or Falling Oil Level

Not having enough oil is just as bad as having old or dirty oil. Once again, check the health and level of your oil regularly to improve the lifespan of your engine.

Topping Your Oil

If you check your oil and it is clean, a simple top-off can do the trick to bring your oil to the recommended level. If you notice over time that your oil goes low despite repeated leveling, you probably have an oil leak which over time can cause problems for your car.

Leaking engine Oil

Poor Fuel Economy

Noticing minor changes in your vehicle’s performance is key to knowing that you need an oil change. When your engine is not properly lubricated it no longer performs at an optimal level.

The vehicle has to work harder to produce the same speed or power resulting in increased fuel consumption and reduced fuel efficiency.

This is a little harder to detect than some of the other signs. Fortunately, most modern cars have modules for measuring fuel efficiency but if your vehicle doesn’t have such a module, endeavor to check in from time to time with an auto electrician to detect reduced fuel efficiency, this is one of the signs your car needs an oil change.

 Fuel economy theme. Empty car gas tank

Ticking Sound When Starting

As soon as you turn your engine on, oil is pumped throughout the needed parts. When your oil is dirty it can take longer and increased the effort to move. This sometimes causes you to hear ticking noises while the car engine is warming up. The ticking is a result of the valves inside the engine working harder to move the dirty oil.

Exhaust Smoke

There is a monumental difference between vapor coming from your vehicle in cold weather verse exhaust smoke. Cold weather vapor is much more invisible or transparent and will disappear almost as soon as it comes out.

Car exhaust smoke is much thicker, sometimes looking blue or grey, and smells like oil. This can be the sign of something more serious however checking your oil is a great way to begin diagnosing the problem.

 Exhaust Smoke

Strong Smell of Oil in the Cabin

Paying attention to the change in smell inside the cabin of your car could signal that your car needs an oil change. Similar to exhaust smoke, perceiving the odor of oil inside of the vehicle cabin, is another sign your car needs oil or an oil change.

Sometimes the oil smell can be hard to detect vs the smell of gasoline. In any case, if you can smell engine fluids burning inside your vehicle, it’s time to make an appointment with an auto mechanic.

Shaking While Idling

If your car shakes while idling, this is another sign your car needs an oil change. Old or dirty oil thickens and does not do its job of lubricating the engine parts optimally. This metal friction can create vibrating or shaking if bad enough whilst driving.

This shaking is more noticeable when the car is idling so if you have this problem, avoid idling as much as possible and make an appointment with an auto mechanic to diagnose and solve this problem.

How To Change Bad Engine Oil

Have you discovered your oil is bad and needs a change? These steps will guide you through the process.

  • Check the type of oil needed.
  • Get together your filter, wrenches, and other supplies.
  • Prepare your vehicle. You want to lift the car high enough to give yourself room to work under it or use an underground work-hole or even rolling ramps. Whether you use a hoist, ramps, or jack stand, make sure you are being absolutely safe. see a practical guide here
  • Locate the oil filter and drain plug.
  • Drain the oil. Place a bowl or can which has at least a 5-liter capacity, this is because a lot of oil could be in the crankcase.
  • Tighten the drain plug very well to avoid any leakages
  • Change the oil filter. This is to avoid introducing dirt into the new oil
  • Add the new oil.
  • Check the oil level and add till it’s okay.
  • Check for leaks

Here is a video on how to change bad motor oil

Key Takeaways!

  • Changing the oil of your car is very important to the health and lifespan of the car.
  • Check regularly for color and texture change of your motor oil
  • Listen to your engine especially while starting your car. This can help you detect if your oil is due for a change or top-up.
  • The use of engine oil in cars varies. Know what suits the model of your car.
  • Drive safely, all the best!

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