When synthetic is required
Many newer engines — especially turbocharged ones and those that use low-viscosity grades like 0W-20 or 0W-16 — specify synthetic oil, and in practice those grades are almost always synthetic. Your manual will say “synthetic” or name a specification that only synthetic oils meet. See what oil does my car take.
Does synthetic mean fewer oil changes?
Only if your manufacturer’s schedule says so. Many schedules with long intervals already assume synthetic oil. Putting synthetic in an engine whose schedule calls for shorter intervals doesn’t automatically let you stretch them. See how often to change oil.
Common questions
Can I switch from conventional to synthetic?
For most cars, yes — as long as the oil meets the grade and specification in the manual. You can switch back too.
Is synthetic worth it if my car doesn’t need it?
It can offer extra protection in very hot or cold climates, for towing, or for lots of short trips. If none of those apply, oil that meets the specification is fine.
Can I mix them?
Topping up with a different type of the same grade won’t harm the engine. That’s essentially what a blend is.