How often should one change fully synthetic oil?
On One Hand: Conventional motor oilEuropean drivers change oil far less than Americans, with apparently few negative consequences. Since the 1980’s, many US auto manufacturers have relaxed the intervals for oil changes to as long as every 5000 or 7500 miles, replacing the three month/3000 mile standard recommendation.On the Other: Synthetic lubricantsSome experts claim far fewer breakdowns in the lubricating properties of synthetic oil and that friction surfaces show significant decreases in wear. However, in-service tests of both types of oil can show that the ability to protect and lubricate internal engine surfaces does occur. With synthetic oil, it happens far later and to a lesser degree than with conventional oil.Bottom LineSynthetic oil has compelling arguments for its use. Independent laboratories can test small samples of oil, analyze the substance and provide a written report with an expert opinion. Results will state whether the oil was overused, still has plenty of service
