The engine oil is one of the essential liquid needed by any engine in order to run smoothly, the major function of the engine oil is to lubricate the moving parts of the engine in order to reduce wear and tear caused by friction from the engine moving parts, as result of that the engine is always equipped with an inbuilt mechanism that helps the engine oil to be pumped from its reserve part in the engine known as oil sump to the other parts of the engine for the purpose of lubricating the engine.

Besides lubricating the engine, the engine oil also assists in the cooling of the engine parts during the reciprocating actions of the piston in the wall of the combustion cylinder otherwise known as the combustion chamber. The possibility of helping in the cooling and the percentage of the temperature reduction completely depends on the type of the engine.

Most of the engine oils in the market were made to have high viscosity while some were made to have low viscosity, though many people attribute the quality of an engine oil to its viscosity but research in most engineering bodies had shown otherwise, rather one should be more concern on the type of engine the oil is meant for and power output expected from such engine.

Most engine oils with low viscosity are seen as the quality types due to their appearance while the ones with high viscosity are always seen as bad engine oil due to the fact that they flow readily when pouring them into the engine but all those assumptions are wrong and those mostly using such criteria for determining the quality of an engine may be novice and lacked proper understanding of the working principle of an internal combustion engines. The engine oil is good for a particular engine may become bad for another engine, it is all determined by the materials of the engine, its design, burning fuel or type of fuel, power output, the speed of the engine, etc.

The next criteria some people use in determining the engine oil quality which might be wrong is the color of the engine oil, some engine oils appear colorless just as water appear while some do have the thick color of blue, green, or any other color. The fact is that many refer to the colorless types as being more superior in quality than others attributing its colorless nature as an evidence of lack of impurities and a well-refined engine oil, while the colored types are seen with an opposite view. But the simple truth is that assumption could be wrong because some of the colored engine oils have some additives added inside which are meant to be of great help to the lifespan of the engine as well as increasing the duration in which the engine oil is meant to stay in the engine before it can be changed. While the assumption could be right when viewed with respect to the appearance condemned oils which do appear black or brown in color, some individuals who usually manipulate the engine oil markets could go to a local place and have the condemned oil refined and then added another additive and colored such that it can be difficult to notice that they are counterfeit, such people can insert the name of any brand to the engine oil and sell it to the market, such had damaged the reputation of most engine oil manufacturers, and such action is a very serious criminal offence in Nigeria which are usually handled by industrial courts established by the federal government.

Nevertheless, the color or appearance of an engine oil has nothing to do with its quality and good or bad performance in any engine, rather it the contents of the additives and the engine oil that determines it alongside the type of engine it is used for.

However, the signs from the engine after the engine oil had been changed could show whether such oil is good for the engine or not, below are some of the signs:


When an engine is operating with a very loud sound it is an evidence of high frictional occurrences in the engine which are taking place without adequate lubrication, the major source of loud sounds from the engine are, the combustion chamber of the engine, the reciprocating movement of piston and its rings on the wall of the combustion cylinder, the engine bearings located at different places in the engine, and the exhaust cylinder of the engine, while the exhaust cylinder does not require any lubrication, the entire parts of the rest requires lubrication though the volume of oil required from each part may vary, because some part requires more oil than the other, the piston and its rings requires a good quantity of lubricating oil followed by the engine bearings, the combustion chamber may not require any engine oil in it because its inclusion in the compressed air-fuel mixture would lead high release of carbon mono oxide which causes the engine to be producing thick black smoke from the exhaust hole for this reason lubrication oil is not needed in the combustion chamber.

A sign that an engine oil is good for the engine is when the sound is able to reduce to a significant level after changing the engine oil, the reason for that is because the oil is able to penetrate into the various parts of the engine such that the friction in the moving parts is properly controlled. The presence of a good engine oil between the cylinder wall and piston rings will reduce the noise coming from that source. The presence of lubricating oil in the bearing of the crankshafts and other moving parts of the engine will also reduce the noise coming from that source. If an engine had stayed in an engine for a long period of time it would affect the viscosity of the engine oil and the engine oil might have accumulated so many particles from the wear and tear of the moving parts of the engine such that it becomes difficult for it to penetrate effectively into various parts of the engine, so a change in the engine oil of an engine would ensure the presence of the lubricating oil in various parts of the engine.


There are many factors that could cause the instability in the power of an engine such factors may include presence of bad engine plug, but it has been observed that bad and insufficient lubricating oil can also affect the power out of the engine and cause it to be fluctuating, this is common in the internal combustion engines.

Hence, a good engine oil will make the engine power output to be stable after adding it inside the engine.


The excess smoke coming out of the hole of the exhaust is a result of excess carbon mono oxide released in the combustion chamber when the power stroke occurs, the cause for this may be as a result of bad fuel in the engine or as a result of lubricating oil finding its way into the combustion chamber, the factor that may give opportunity for this occurrence is bad or broken piston ring.

An engine oil that had been in the engine had accumulated so much dirt from the engine including carbon monoxides but the new one had no such particles hence, having it inside the engine would produce less smoke in the exhaust due to the non-carbon monoxide inclusion. Also, the viscosity of the engine oil has not been affected by the engine dirt therefore, the lubricating oil may not easily flow into the combustion chamber even if the piston rings are bad.


A good engine oil would help to prolong the life of the piston rings by ensuring that no dirt is pushed into the wall between the cylinder and the piston rings, so if the oil is dirty it could affect the lifespan of the piston rings by causing excess wear and blocking the clearance in the wall with dirt of other metallic particles in the lubricating oil.


Vibrations are mostly caused by misalignments in the engine parts, most misalignments are caused by the prolonged wear and tear in the moving parts of the engine, an old engine oil may have no viscosity to remain in the space created by the action of wear and tear in the engine while the engine is in operation, though the engine oil pump may be working properly but the oil may find it difficult to remain in such small spaces for a long time especially when the location is in vertical position, therefore to have a reduction in the vibration coming from the engine after changing the oil is a sign that the engine viscosity is good for the engine.


The high operating temperature in the engine usually leads to overheating which can cause a sudden shut off the engine followed by some damages in most moving parts of the engine. It is a situation that any engine owner doesn’t want to encounter. The major reasons why engines operate at high temperature are low or insufficient cooling system such as water, the wrong metallic material the engine was made from, insufficient or bad engine oil and overloading of the engine.

A good lubricating oil helps the engine temperature to be controlled while in the operational stage.

  • Yum