Engines need oil that is thin enough for cold starts in colder temperatures and thick enough when the engine is hot. This is why cars use a multi-grade, or multi-viscosity oil. The W in the oil designation refers to its weight or viscosity. The lower viscosity (5) of the multigrade oil makes it flow more easily, improving fuel efficiency and cold weather starting. Newer vehicles generally specify 5W30 oil year-round while older vehicles often need 10W30 in summer and then switch to 5W30 in winter.
Motor oil also removes dirt, metal shavings and other impurities from the engine and captures them in the oil filter which reduces wear on your engine. At higher temperatures, oil carbonises and most of the black residue that you see in your used oil when you change it is a result of burnt, carbonized, and deteriorated oil.
When you purchase oil, look for one that is “Energy Conserving.” Look at the label on the right side of the container where it shows the grade of the oil (e.g. 5W30). At the bottom of this label the best oils will indicate that they are energy conserving. These oils can save you as much as 2.5% on your fuel consumption.
Many vehicle owner manuals are still recommending changing your oil every 5,000 kms, however with today’s modern oil and engine technology intervals can be as much as 10,000 kms.
Re-refined motor oil is recovered from used product and rejuvenated for reuse as an alternative to “virgin” oil products. The necessary detergents and additives are replaced in the oil, and impurities are removed. The result it has similar properties to mainstream motor oil products and performs as well as motor oil from original sources. Re-refined oil is certified with the EcoLogo mark. If you change the oil yourself, take the old oil to your service station for recycling. One litre of engine oil can contaminate 2 million litres of water!
Synthetic oil is an alternate to petroleum based oils and generally increase your fuel efficiency by up to 10%, particularly under extreme weather conditions. Synthetic oils are an engineered product offering superior flow characteristics and resistance to viscosity breakdown. Oil change intervals vary with synthetic oils, but can more than double the number of kilometers that you drive between changes. Consult your owner’s manual and the oil manufacturer’s information to determine the exact interval. Synthetic oil is more expensive than conventional motor oil. You need to do the math considering costs and change intervals. They are sometimes required for some high performance engines, and used by those wanting that performance.