12-17-2011, 04:03 PM
High mileage oils (synthetic or not) are not "heavier" unless you specify a higher viscosity. However, they carry some additional additives that aren't in regular oil. They contain a burnoff inhibitor that supposedly reduces how much oil your engine is burning and a seal swelling agent that will help old cork and paper seals retain their integrity. If your engine is prone to leaking and burns oil I suppose they might help a little bit. If you're engine is not using a lot of oil then don't bother.
Early synthetic oils caused leaks because the swell-seal characteristics of the oils were not as effective as mineral oils. That was many years ago and is no longer valid.
To my mind, synthetic makes the most sense in all cars, and it pretty much pays for itself in less engine wear, better gas mileage and doubled oil change intervals (you can safely go to 10,000 mile intervals with synthetic oil because of its thermal breakdown characteristics). You still need to change the filter every 5,000 though.
Synthetic blends have nothing going for them except higher price as far as I can tell.
Early synthetic oils caused leaks because the swell-seal characteristics of the oils were not as effective as mineral oils. That was many years ago and is no longer valid.
To my mind, synthetic makes the most sense in all cars, and it pretty much pays for itself in less engine wear, better gas mileage and doubled oil change intervals (you can safely go to 10,000 mile intervals with synthetic oil because of its thermal breakdown characteristics). You still need to change the filter every 5,000 though.
Synthetic blends have nothing going for them except higher price as far as I can tell.