Synthetic oil molecules are also very consistent in size and shape and offer superior lubrication. The fully synthetic oil works optimally at low and high temperatures valvoline coupons or under extraordinary stresses. The biggest problem with mineral oils is that they provide little or no lubrication and protection from friction-induced heat.

For example, a 10W-30 oil indicates the viscosity of the liquid when it is cold, with “W” indicating that the SAE approves the oil for lower winter temperatures. A weight of 10 is thinner than a weight of 30 and beneficial in cold, as a thinner engine oil allows for easier engine start-up and reduced voltage. The second number, “30”, indicates that the viscosity of the oil is heavier and offers more protection at warmer temperatures.

The latest API service standards are SP for gasoline engines and CK-4 for diesels. These letters are based on a group of laboratory and engine tests that determine the power of the oil to protect the engine from wear and high temperature deposits and sludge. API has a full list of these standards here in case you’re curious, but be sure to buy an oil that has been tested to a current standard. At the time of writing, this includes SP, SN, SM, SL and SJ for gasoline engines and CK-4, CJ-4, CI-4, CH-4 and FA-4 for diesels.

They are typically used to improve performance and provide better protection than conventional oil. This makes them less volatile and less susceptible to evaporation, reducing oil losses and improving fuel consumption. Mineral engine oils are made from refined crude petroleum products. The process omits natural contaminants and unnecessary hydrocarbons. Although mineral engine oils are cheaper, they are thicker in shape and often require oil changes.

But technology has balanced the act by introducing multigrade oil. This oil had the cold viscosity of one oil of one quality and the hot viscosity of another. We now had two numbers sandwiching the “W” on the containers. For example, engine oil with ’20w50′ simply told us that the oil works as a single ’20w’ cold quality and a single ’50w’ hot quality. It has maintained its viscosity, making it thin enough to safely start the car from the cold, while retaining enough body to remain effective when it’s hot.

Chemically modified to improve their performance, synthetic oils contain fewer impurities than mineral oils and are therefore of better quality. They are designed for powerful engines, making them more suitable for more modern vehicles and motorsport. Synthetic oils make it easy to cold start the engine while withstanding high operating temperatures. You can go longer between oil changes, for diesel and gasoline engines. Instead, they are an artificial fluid designed to lubricate engines. They offer significant improvements over conventional oil with additives and formulas that help keep your engine clean and reduce friction.