How do you change your oil?

Instead of making motor oil with the conventional petroleum base, "true" synthetic oil base stocks are artificially synthesized. ("Commercial" synthetic oils are in fact Group III mineral base oils.) True synthetics include classes of lubricants like synthetic esters and polyalpha-olefins. Higher purity and therefore better property control means Synthetic oil has good mechanical properties at extremes of high and low temperatures. The molecules could be made large enough and "softer" to retain good viscosity at higher temperatures, yet branched molecular structures interfere with solidification and therefore allows flow at lower temperatures. Thus, although the viscosity still decreases as temperature increases, these synthetic motor oils have a much improved viscosity index over the traditional petroleum base. Their specially designed properties allow a wider temperature range at higher and lower temperatures and often include a lower pour point. Because the viscosity changes much less with temperature, these synthetic oils need little or no viscosity index improvers that are used with the traditional petroleum based oils. The viscosity index improvers are the oil components most vulnerable to thermal and mechanical degradation as the oil ages and wears out. Because these synthetic oils have little or no viscosity improver content, they do not degrade as quickly as traditional motor oils. However, they still fill up with particulate matter like the conventional oils do, so the oil filter still fills and clogs up with time and must still be changed periodically. Synthetic oil still needs to be changed periodically; but some synthetic oil suppliers suggest the intervals between oil changes can be longer, sometimes as long as 10,000 - 15,000 miles between oil changes. The same SAE system for designating motor oil viscosity applies to synthetic oils also.