Primary role of engine oil is to lubricate moving parts in an engine. Oil keeps the parts running smoothly while minimizing friction and engine component wear. It also draws heat away from lubricated engine components before the oil is cooled via air in the sump before being recirculated through the engine.

Additionally, motor oil also has several chemical compounds that improve its performance and help keep your engine clean by removing impurities.

Modern oil is much more advanced than it used to be, which means we no longer have to change the oil every 3,000 miles. The role of oil however hasn’t changed much and it performs the same functions with greater efficiency. If oil isn’t changed it eventually thickens and becomes tar-like as it breaks down and becomes what mechanics call engine sludge.

The first problem you will face is debris and contamination being deposited throughout your entire engine. Your oil keeps the engine clean by picking up dirt and anything else that shouldn’t be there filters it through an oil filter. When the oil filter becomes clogged with contaminants, the dirty oil is cycled back through the engine.

It’s better to get your oil changed more frequently than not as motor oil degrades over time. The longer you leave old oil in your engine, the more it will break down. Additionally, its lubricating and cooling properties will greatly diminish. 

Fully Synthetic Oil

Fully synthetic motor oil has been completely chemically engineered to make the molecules uniform. Therefore, it performs more consistently with fewer impurities than conventional oil molecules. Fully synthetic oil has higher viscosity levels, better resistance to corrosion, and oxidation. It is typically the most expensive type of oil available and is recommended for high-performance engines or vehicles that are used for towing.

Semi-Synthetic/Synthetic Blend Oil

Semi-synthetic motor oil is a hybrid that combines synthetic and conventional base oils for improved resistance to oxidation with exceptional low-temperature properties. It is a good option for those who want extra performance from conventional oil without the high price tag of fully synthetic oil.

High Mileage Oil

If you drive a car that has traveled more than 75,000 miles you may need to switch to ‘high mileage oil’. This type of oil contains unique additives to protect seals, prevent oil leaks, and reduce oil burn-off, engine smoke, and engine emissions.

Conventional Oil

Conventional motor oil is considered the industry standard. It is manufactured from crude oil that has been refined and is available in a wide range of viscosity grades. It is mostly used in late-model cars that are driven daily and don’t require special protection.

The most important property of oil is its viscosity rating. Look at the label of any bottle of oil, and you will find a series of numbers and letters, for instance, 10W-40. This is the ‘grade’, which indicates that particular engine oils viscosity.

Viscosity is a universal measurement of the movement of a fluid. It refers specifically to the oil’s resistance to flow at a certain temperature. This can be broken down into two key characteristics: kinematic and dynamic viscosity. Understanding these will help you choose the best oil for your vehicle.

Kinematic viscosity measures the oil’s internal resistance to flow and shear under gravitational forces. The lower an oil’s viscosity is, the faster it will flow. Kinematic viscosity also determines the high-temperature grade of oil. On an oil graded 10W-40, Kinematic viscosity refers to the ‘40’.

Dynamic viscosity is a measurement of the amount of energy needed to move an object through the oil. Dynamic viscosity also determines the low-temperature grade of oil. On an oil graded 10W-40, dynamic viscosity refers to the ‘10W’. The ‘W’ literally stands for ‘winter’ – an indication of the oil’s resistance to cold at engine startup.

What it all comes down to is that the lower the first number is, the less resistance to flow the oil has when you cold start your engine. And the lower the second number is, the less resistance to flow the oil has at normal operating temperature. Motor oils get thicker as the temperature cools and thinner when heated. Therefore, thinner oils with low viscosity provide more protection at colder temperatures. Thicker oils with high viscosity provide more protection at hotter temperatures.

Always consult your vehicle owner’s manual as using the wrong motor oil can cause engine problems.

Using an oil that is lighter than necessary can cause excessive engine wear as the oil is too thin to form a protective film between the parts. Using a heavier oil than necessary will decrease fuel economy, increase engine load, and slow the rate of oil flow. Both instances will lead to shorter engine life. Your mechanic will know if you are using the correct oil for your vehicle, and when it’s time to switch to a heavier or lighter grade.