These products react differently with engine/transmission gaskets. It is best to select a product when the car is new and stick with that product to avoid possible gasket failure (leaks).
Yes, there is no harm in switching back and forth.
Synthetic oil is a chemically made substitute made from petroleum components as opposed to non synthetic which is made from crude oil.
Oil usually refers to petroleum lubricant. It is refined product of crude oil pumped from underground oil fields around the world. Synthetic oil is lubricant manufactured as a substitute for petroleum lubricant, it was first developed by Germany during WWII to make up their shortages in oil. Semi synthetic oil is a mixture of petroleum lubricant and syntetic lubricant.
Synthetic oil works better in some engines than does petroleum-based oil. Nylon is synthetic.
Yes
When I first asked the dealer about switching to synthetic oil, he said the it already used a mixed synthetic and regular oil and that 100% synthetic was unnecessary.
Look at the can it came in or do an oil analyst if it is already in the engine. What difference does it make?
Yes, although don't expect damage to be immediate. Petroleum oil is refined and synthetic oil is engineered. The difference being the molecular structure is unstable and varies in petroleum oils. Synthetic oil has a more stable molecular structure that is less susceptible to shear stresses. I use Amsoil in particular, because it outperforms all other synthetics, but ANY synthetic is better than conventional. If your mfr requires synthetic, for sure do not compromise!
I switched to full synthetic engine oil in 2001 and have no oil leaks on my 1995 Ford What makes you think you will have leaks? And if you think you will have leaks then why would you use synthetic? You will have no leaks that you would not have with conventional oil.
It's okay to use Synthetic oil on any vehicle but bare in mind, if your vehicle has previously run on regular oil you will need to drain all the oil out completely in order to switch to synthetic, once you run on synthetic oil though you have to keep the oil synthetic because switching between different types of oil will really mess up your vehicle.
Yes, you can even mix synthetic with conventional oil.
5W/30 synthetic oil is best, conventional petroleum base motor oil is acceptable but inferior, Brand does not matter with full synthetic, but beware, many are blends