Hi Hhummdrumm, The vehicle manufacturer sets oil change intervals and we do not recommend extending oil drain intervals beyond the manufacturer's recommendations. Anything else outside of the recommended interval may void your engine warranty and lead to bigger issues further down the road. Besides, part of the role of an engine oil is to clean and neutralize dirt and combustion by-products that the engine produces while just driving down the road. Engine Oils are also designed to hold all of that bad stuff in suspension, so that when the oil is changed all of the bad stuff is drained out from the engine as well. So, whether it is a synthetic oil or a cheaper conventional mineral oil, it doesn’t make sense to keep that bad stuff circulating around in your engine any longer than what the OEM recommends as their oil drain interval. However, the use of synthetic engine oil does offer advantages over conventional oils when used under extreme temperature conditions. At extremely low temperatures, synthetic motor oils have better flow properties and therefore, are easier to pump during engine start-up (before the engine is warm). This provides a better oil supply to the parts that need lubrication. Under operating conditions, which generate extremely high temperatures, such as towing heavy loads or sustaining high speeds for long periods of time, synthetic oils also offer added protection. This added protection occurs because the oil is more resistant to oxidation and thermal breakdown. Synthetic oils also have a lower volatility, resulting in less product loss at the higher temperatures associated with these extreme conditions. - The Pennzoil Team
