Why using wrong engine oil in your car is a bad idea

At some point during the last three months, getting some types of engine oil has been unprecedentedly difficult, in particular, the 5W-30 variant. Following this scarcity of sorts, it would not be unexpected that many car owners resorted to using ‘alternatives’ as their mechanics may have advised; ‘Oga everything na the same’, or ‘This one is even better than that 5W-30, my other customers use it’.

Taking that advice would be as dangerous as the likelihood of getting your car’s engine damaged, which would of course cost far more than the five to eight litres of the proper engine oil that should have been used.

The oils vary as one may have noticed; 0W-20, 0W-40, 5W-30, 5W-40, 10W-40, 15W-40, 20W-50, and that’s not at all, performance specifications also have to be noted.

As noted in an article on, before we delve into the nitty-gritty of engine oil, go ahead and pull out your car owner’s manual. In it, you will find clear guidance on viscosity, certifications and specifications that the manufacturer recommends for your engine.

For the good old Tokunbos that may not come with a hardcopy manual, these can also be downloaded as PDF to your phone or other device.

So, how do you know the right engine oil?

Inside your vehicle owner’s manual, you will find the original equipment manufacturer’s (OEM) motor oil recommendation. Look for a couple key points:

• Engine oil viscosity

• Performance or industry specifications the oil should meet

The OEM will recommend a motor oil of a specified viscosity that meets the appropriate performance or industry specifications. For example, the OEM might tell you to use a 5W-30 oil that meets the API SN PLUS specification, or equivalent, notes an article.

When choosing oil for your car, at the very least use an oil that hits those two checkboxes.

Read also:  Why you should scan that used car before buying it

Why does it matter?

According to Mobil, to understand Viscosity and why it matters, think about honey and water. When you pour them from a cup, both liquids flow at different speeds. That’s viscosity! For engine oils, viscosity determines the speed it flows to protect the engine. A greater number represents a higher viscosity, which means the oil is more viscous and more resistant to flow.

If you use a viscosity that is too high, you’ll experience unresponsiveness in your engine. This means that more energy (i.e. fuel) is needed for your engine to overcome the oil’s resistance to flow, in order to reach critical engine parts. Newer engines typically require ‘light’ engine oil.

According to Amsoil, Viscosity is the most important property of engine oil. Your engine was built to use a motor oil of a specific viscosity. Today, 5W-30 is the most widely recommended oil viscosity. The “5W” rating refers to the oil’s viscosity when it’s cold (40ºC). The “30” rating refers to the oil’s viscosity when it’s hot (100ºC).

Oil thickens when it’s cold (it’s viscosity increases). Alternatively, it thins when it’s hot (it’s viscosity decreases).

Engine oil is the lifeblood of your car’s engine. Without it, vehicles simply wouldn’t function. Motor oil protects your engine by lubricating parts, which in turn minimizes heat and friction; the two biggest enemies of engine components, says

Differentiating engine oil types

Synthetic engine oil

Synthetic engine oil offers the best protection and performance of the three options. It doesn’t contain the impurities inherent to conventional oils, meaning it provides improved resistance to extreme heat, better wear protection and maximum cold-flow properties when the temperature drops. That translates into a cleaner, longer-lasting engine, notes AMSOIL.

Mobil, however, further notes that full synthetic oil can last more than 10,000km between oil changes. With a longer oil change interval, you don’t need to visit your mechanic quite so often.

Being more “slippery”, full synthetic oil has better anti-friction properties than mineral oil. With better engine responsiveness and fuel economy, it also helps extend your engine life. This is especially useful if you drive in stop-and-go city traffic

Semi-synthetic engine oil

Semi-synthetic or synthetic-blend, is simply a mixture of synthetic and conventional oils. It’s designed to provide improved protection compared to conventional oil without the higher initial price of synthetic motor oil.

The drawback, according to AMSOIL, however, is that there’s no telling how much “synthetic” is in your synthetic-blend motor oil since there are no industry regulations that require oil companies to publish that information.

Conventional (mineral) engine oil

Unlike synthetic oils, which are manufactured using a chemical-reaction process, conventional oils are refined from crude oil. The refining process removes some impurities inherent to crude, but it can’t remove them all. As such, conventional oil contains molecules detrimental to lubricating an engine, such as sulphur and waxes.

Conventional oil is more prone to cause harmful deposits when exposed to heat and thicken in the cold. This makes it more difficult to start your engine, and chemically breakdown sooner, requiring more frequent changes.

As Mobil notes, these last 5,000km, on average. This means you need to change your oil more frequently– costing you dollars and precious time. But if your engine is older and has always used mineral oil, continuing with the oil will still provide beneficial protection for your engine.

AMSOIL caps this by saying; if you’re driving a beater that heralds its arrival with a plume of blue smoke and a cacophony of slapping pistons and knocking rods, use the cheapest oil that meets the OEM requirements.

But if you want the best for your engine, use synthetic motor oil.

What are the main benefits of engine oil?

As seen on, engine oil firstly avoids costly repairs. Without a lubricant, the engine would quickly be seriously damaged. In strict terms, this is what a quality engine oil offers.

• Ensures a longer engine lifespan

By reducing friction between parts and by cleaning the entire engine, engine oil prevents the engine from clogging and becoming damaged. Mechanical parts last longer and corode less. The engine therefore performs greater and its lifespan is increased.

• Ensures proper running of the engine

An oiled engine runs better. Good lubrication is in fact essential to avoid serious mechanical damage. In addition to engine performance, the cost of maintenance is also affected.

• Decreases fuel consumption and CO2 emissions

If an engine oil is overused, or if it’s level is too low, the resulting friction alters the engine’s energy efficiency, which in turn increases fuel consumption. A high-performance oil also reduces polluting discharges in the atmosphere.

Using the wrong engine oil for your vehicle can lead to reduced lubrication and shorter engine life, need we say more?

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