The SAE (Society of Automotive Engineers) have a standard for indicating low and high viscosity engine oils for the right temperature. At low temperatures, synthetic oils flow easily and maintain viscosity at high temperatures. But synthetic oils are able to do the same without the incorporation of additives. Conventional mineral oils are mixed with various additives to help change the viscosity index. These viscosity changes are related to engine-protection and efficient-operation in all conditions.Ī lubricant’s resistance to thinning at higher temperatures is known as viscosity index. A higher viscosity lubricant will be less fluid and thicker in nature whereas oils with low viscosity are thinner and flow freely. The oil becomes thin at high temperatures and thick at low temperatures.

They lubricate the engine responsibly and accordingly, hence considered more dependable.Įngine oils are affected by changes in temperatures. At high temperatures, multigrade oils oppose thinning out and in colder conditions, they remain fluid. They show oils that have two viscosity grades are since, indicated the same as monograde oils are but adding another number. They flow smoothly without thinning out and are most useable for present-day vehicles. These contain the best of both worlds and are not affected by both low and high temperature. For eg SAE International engine oils 8, 12, 16, 20 and so on. High engine viscosity grades use only numbers to indicate and are most suited to higher temperatures. These are more fit for engine-use in colder temperatures. According to SAE International standards, they are 0W, 5W, 10W, and so on. The symbol of low engine viscosity grades is with a ‘W’ at the end. These engine oils are more suited to low temperatures and cater more to older vehicles. Based on the types of viscosity grades or standards, We can differentiate them into monograde and multigrade oils. This will avoid wear and tear in the engine parts and act as a layer of protection. As the lubricants will be thicker and highly viscous, the flow of the oil through the engine will be slower. On the contrary, engine oils with a high viscosity grade are best in hotter temperatures. This helps in preventing a cold engine start in chillier conditions. It will not be thinning out and have better fluidity because the oil has low viscosity. Engine oils have viscosity grades to show the engine oil’s adapting to varying high and low temperatures.įor example, a low engine oil viscosity will perform better in colder temperatures. The viscosity grade of an engine tells you how smoothly or easily the oil flows in your engine at different temperatures.

Define viscosity of oil