Join Date: Aug 2013
Location: Connecticut, USA
Car Year: 2001
Car Model: Forester L
Transmission: 4 Speed Auto
Feedback Score: 0 reviews
One thing to keep in mind about synthetic oil is that you don't want to change to/from dino oil suddenly, at least go for 2-3 semi-synthetic oil changes before changing full one way or the other. And, yes, synthetic is better in all ways except price.
Also, don't change your oil early on the first change, do it exactly on time - there's zinc and molybdenum added to the oil to help break in your rings and other small parts.
The reason for not switching suddenly is microfractures - as your metal fatigues, microscopic fractures are created in the crystal structure of the metals. Since dino oil uses pour point depressants and other additives (since a 5W30 starts usually as a straight 20 or straight 30 weight oil), those fill in the cracks. Synthentic oil doesn't need these, and when you change suddenly it will pull them out and your motor will start burning oil, particularly on an older motor. Synthetics actually have metal conditioners that have to work in to the metals, and because they are actually made as a variable weight from scratch, they have different molecular chain lengths that work their way in to the parts. At the end of driving 20k+ miles on full synthetic, the parts are actually lubricates from inside of the structure of the metal, so for cold starts or in an oil starvation situation you still have some lubrication.
Overall, synthetic is better, and if you keep using it over the long term it helps your motor last a very, very long time.