We all periodically change our engine oils to protect and improve the life of our vehicles and their engines. But how much do we really know about it? A lot of us just follow what our mechanics ask us to do or what the company service centers do. But like us, there are many who actually take matter in their hands and choose what products their vehicles will experience. Let us start with the basic types of engine oil, namely – Conventional Engine Oils, Synthetic Blend Engine Oils (Semi-Synthetic), Synthetic Engine Oils, High-Mileage Engine Oil.
Conventional : Conventional engine oils can be formulated in different types of viscosity grades and levels of quality. Conventional engine oil is recommended for vehicles with simpler engine designs and also the owner should not have a severe driving/riding style.
Synthetic Blend (Semi-Synthetic) : Synthetic blend engine oil uses a mixture of synthetic and conventional base oils for added resistance to oxidation (compared to conventional oil) and provide excellent low-temperature properties.
Synthetic : Synthetic engine oil has gone through a chemically engineered process. Synthetic oil molecules are more uniform in shape with fewer impurities and have better properties than conventional oil molecules. In general, synthetic oil has better extreme high temperature and low temperature performance. Synthetic oils are generally formulated with higher performing additives.
High-Mileage : High-mileage engine oil is specially formulated for older vehicles or newer vehicles with over 1,00,000 km. High-mileage engine oil, with its unique additives and formulation, helps to reduce oil burn-off, and helps prevent oil leaks that may occur in older engines.
So here are your types of engine oils and according to our use and type of vehicle, we can choose the one most suited to our vehicle. But you must have noticed some numbers and alphabets written on them, so let us break them down for you.
The Society of Automotive Engineers (SAE) has developed a code system for grading the engine oils on the basis of their viscosity characteristics and temperature based performance. Viscosity is a fluid’s resistance to flow. Fluids that are thin (like water) have a low viscosity and fluids that are thick (like honey) have a high viscosity. The engine oil also changes in viscosity measurement as it is heated or cooled.
The SAE grade numbers denote two types of measurements –
One which measures the performance in cold temperature, i.e 0W, 5W, 10W, 15W, 20W and so on. The “W” here denotes winter grading and it has been carried on from the days when oils used to be only mono-grade oils. The number before “W” is the performance grade of the equivalent base engine oil at 0o C, but do not confuse these numbers with viscosity. These numbers mean how good the performance of that respective engine oil would be in cold temperatures.
Now the other set measures the performance during working in high temperatures, such as 8, 12, 16, 20, 30, 40 and so on. The document SAE J300 defines the viscometrics related to these grades. The most common grade is 10W-30. Now these numbers are determined by two types of viscosity, Kinematic Viscosity and Dynamic Viscosity.
Kinematic viscosity is determined by the time a standard amount of fluid flows through a standard orifice, at standard temperatures. The longer it takes, higher the viscosity and thus that respective oil will have higher SAE code. Thus bigger numbers are thicker and they operate better at higher temperatures. Meanwhile, Dynamic viscosity is the exact opposite, it defines the “W”. The viscosity levels are measured at low temperatures from -35o C to -5o C which results in grades from 0W to 25W. These are the lowest possible temperatures at which an engine can be started.
Multi-grade viscosity engine oils are able to perform at a wide range of temperatures. Multi-grade viscosity engine oil flows well at low temperatures, but still protects the engine at high temperatures. For example, if we take the most common grade 10W-30 and compare it with 0W-30 and 5W-30 then they will flow better in colder temperatures and still protect the engine equally well at higher temperatures.
It is not much of a hassle, a few extra minutes at every periodic maintenance and your vehicle gets long-term benefits. The right choice of engine oil can also prolong the life of your engine providing better fuel efficiency and lower emissions. So at the end, the choice of engine oil always depends upon your geographical location, type of engine and the way of driving/riding.