The best motor oil for you car depends on the car. Many old cars can only handle regular motor oil.
That's okay.
No, you can even mix synthetic with conventional oil. It will do no harm at all.
Yes but once you do there is no turning back and no mixing regular motor oil ever again with the synthetic oil....only straight synthetic....or use semi synthetic....now that can be mixed with regular motor oil in a pinch.
Synthetic oil or a blend of Synthetic and regular oil is much better for your vehicle than regular oil alone. Synthetic oil is MUCH more expenshive. If you change your regular oil every 3 months or 3,000 miles I will be fine.
yes it is fine but of course synthetic is the best to use if you can. Double check your oil requirements with your owner's manual. If it states that normal oil is okay, then go ahead. If your owner's manual dictates Synthetics, then DO NOT switch.
motor oil, of any kind, would kill most plants
Mobil 1 Full Synthetic
Nothing happens, they just mix. You can buy "blended" motor oil.
Amsoil By far the best.
Any major brand synthetic oil.
No. It will ruin an engine. The above answer is 100% wrong. You can mix convention oil with synthetic and it will do no harm at all. When you see them selling Synthetic blend that is what you are buying. A blend of synthetic and conventional oil.
5w-30 is recommended and you can use either regular oil or synthetic.