oil differences ?

Synthentic oil of course is supposed to be more free flowing, and offer more protection. All studies that I have read show that it's really only benificial at the critical points, such as if you should lose all your oil, and keep driving to a shop or something. Which almost no one would ever do. They claim you can also wait longer to change your oil.

High mileage oil is usually thicker, like at least 10W-30, and it's conventional oil with a different combination of additives, to offer more protection and condition seals. Also to form a better seal in the cylinders.

Most people I know have found that conventional oil is just fine. Some claim that a semi-synthetic is the best. I don't know anyone myself that uses high mileage oil.

I have near 117,000 HARD miles on my '95 GA (4 cyl) and still use 5W-30 conventional Quaker State. I still have plenty of "get up" and NO oil consumption.

Tony

I agree with most except the Synthetic oil part. Synthetic oils are not only free flowing but also reduce engine wear due to being slipperier than conventional oils. Therefore they offer superior protection over conventional oils ever will. True synthetic oils like Red Line & Amsoil also offer extended drain intervals due to their greater lifespan before they break down whether that be thermally or chemically.