As the title says: QUOTE: The synthetic oil marketing machine is alive and well!!! Why do you think that you need synthetic oil? Why won’t conventional oil work just as well? Either one lubricates in the same way. It provides a lubrication film between the two moving parts to prevent metal to metal contact. When metal to metal contact occurs, the anti wear additive provides protection. For the most part, the same additives can be placed in either oil. (synthetics don’t accept additives as easily as conventional oils do) The big difference between the two is how durable the base oil is under severe conditions. The mechanism of failure for most engine oils (even yours) is deterioration from combustion by products and contamination by the engine. If it wasn’t for these factors, any oil would last many times longer. The durability of the base stock in conventional oil is not an issue unless some extremely abnormal condition exists. By changing engine oil at the recommended change interval and using API licensed oil, you change it with a good margin for before the oil fails. If you use synthetic oil and change it before a conventional oil would fail, there is no meaningful advantage to using the synthetic oil. I don’t recommend it but .... if you extend your changes, a synthetic would only be an advantage if when you determined the point of failure with conventional oil, you could extend beyond that point with a synthetic. For this to happen the mechanism of failure has to be one that synthetic oil could prevent. With the normal mechanism of failure being deterioration from combustion byproducts and contamination by the engine there is no significant advantage to synthetic unless the oil fails for a different reason than it normally does. So what are you really gaining????? Pump-ability? Only in very cold temperatures. If you live on the North Slope, you may need a synthetic oil to protect you engine at very low temperatures. If you don’t experience extremely low temperatures, conventional oils with viscosity modifiers have a similar viscosity throughout their working range and there is no meaningful difference in pump-ability. Chevron Supreme 5W-30 pour point …….minus 33 degrees F Chevron Supreme Synthetic 5W-30 pour point ….minus 62 degrees F Less volatile? Not a problem in a passenger car or light truck unless there is a very unusual condition. At high enough temperatures the oil will burn off and carbon deposits will be left behind. The OIL has to actually reach this temperature for it to happen. I know, ….I know, the ads have told you there are areas in your engine that get above these temperatures. BUT…. The oil does not get this hot unless it stays in the area and is allowed time to heat up. Oil that circulates through a high temperature area transfers heat to it but is not there long enough for it to reach a temperature that causes damage to the oil. Chevron Supreme 5W-30 flash point …….450 degrees F Chevron Supreme Synthetic 5W-30 flash point ….464 degrees F Thermally Degradation? Thermal degradation is shortening the oil life as a result of high temperatures over a period of time. This would be a problem if your oil were run at unusually high temperatures for sustained period of time. Unless you were operating way outside of the designed use of you engine, you would never see high sustained oil temperatures. If you managed to abuse your engine to this level, my bet is, you will create problems way beyond lubricating oil degradation. I have looked at scores of oil sample reports and have spent a lot of time working in this field and have never heard of the problems that the synthetic oil marketeers claim you have protection against occurring in a vehicle that was maintained in some reasonable fashion. The ad campaigns for synthetic oils make it appear that they happen all of the time. They couldn’t be farther from the truth. Conventional motor oil provides all of the protection you will ever need. UNQUOTE To be honest, hard to argue with his logic. What do you think?