Does Summer driving require thicker engine oil?
Summer temperatures are not a consideration as all engines operate far in excess of ambient temperature. To an engine that operates near 100 degrees Celsius, there is no difference in a mild Spring or the hottest summer day. Cold Temperatures are much more of a concern, as the engine must be lubricated on startup. Thicker oil does not flow well at low temperature. This is why manufacturers specify multi-viscosity oil, capable of handling a wide range of conditions. For instance, 5W20 has the same flow characteristics as five-weight oil at zero degrees Celsius and the protection of 20-weight oil at 100 degrees Celsius. A more detailed article on oil viscosity is in our Detailed Auto Topics section under Oil Viscosity.
