Only if the engine has low miles or no sludge build up - synthetic oil captures the carbon within its molecules and if there is to much carbon buildup (sludge) it will release the carbon into the molecules of the synthetic oil and run it through the engine - once the filter is bypassing there is nothing to keep the "liquid sandpaper" from wiping out the bearings.
No, you can even mix synthetic with conventional oil. It will do no harm at all.
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.
That's okay.
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.
Yes, you can not only switch you can mix synthetic with conventional oil.
Yes, and you can even mix them together.
The best motor oil for you car depends on the car. Many old cars can only handle regular motor oil.
motor oil, of any kind, would kill most plants
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.
If your car originally had full synthetic, then you should go with that. But if it came with regular/conventional oil then it wouldn't be smart to switch unless you have it flushed out because it can cause carbon build-up inside, which will make the motor run harder and heat up more.
Yes, anything mid 80's and up can be switched between conventional oil and synthetic oil. Anything older (that was around when zinc was found in oil, or when cork gaskets were used) should stick to conventional oil. It's actually federally mandated that conventional and synthetic oils be interchangable.
All regular harley's take 20w50 motor oil, regular or synthetic is your choice.