By Jim Kerr
Automobile manufacturers use many methods to improve fuel economy. One that you may not have considered is the use of lighter-viscosity engine oils. Toyota, Honda, Ford, Chrysler, Mazda and Mitsubishi are some of the manufacturers that are specifying the use of 0W-20 synthetic engine oils in some of their vehicles. Toyota has even been using 0W-20 synthetic motor oil as a factory fill in several models since 2006; if your vehicle currently uses 5W-20 conventional oil, then the 0W-20 synthetic oil is an option.
So why would you use 0W-20 oil? First of all, this synthetic oil has excellent stability through a wide temperature range. For example, Mobil1 0W-20 oil pours at temperatures as low as –47 degrees Celsius and protects at oil temperatures as high as 205 degrees Celsius. This is far outside the normal operating range for almost all vehicles.
Vehicles in past decades needed thicker conventional oil with viscosity ratings of 10W-30 or higher. As temperatures went up, the oil would thin out but by having a thicker initial viscosity the oil could still keep moving parts protected. There are many car owners and automotive technicians too who still think you need high viscosity oils to protect engine parts. This may have been true when engine parts were not as precisely made, but now more precise engine parts and the advanced chemistry in 0W-20 oil provides this same protection and has additional benefits as well.
Because 0W-20 flows so well at cold temperatures, it lubricates parts faster during cold starts. Most engine wear occurs during the first couple of minutes after a cold start and fast flowing oil protects sooner; it also allows the engine to crank faster so it can start more quickly. These are real benefits on a cold Canadian winter morning.
Another benefit of 0W20 is reduced internal engine friction, which improves fuel economy in the range of 0.5 to two per cent. This may not seem like much, but improving fuel economy is done in small steps. Every little bit helps and it could save you several hundreds of dollars in fuel costs over the life of the vehicle.
Some of the fuel economy savings result from less power needed to drive the oil pump in the engine – the lighter viscosity oil just flows more easily. Internal engine changes over the years have been made to accommodate thinner viscosity oils. Different oil ring design and roller contact points for the valvetrain reduce a lot of sliding friction.
Engine oil prevents wear by separating moving parts from each other. The oil forms a boundary layer so the parts don’t touch but high spots on the parts can penetrate the oil film and cause wear. More precise tolerances and more accurate machining processes for engine parts help the thinner viscosity oil protect the parts.
0W-20 oil provides the best lubrication under all temperature conditions, reduces engine combustion chamber deposits, reduces vehicle emissions and improves fuel economy. That’s a lot to ask of engine oil, but 0W-20 synthetic is up to the task.