If I go to a synthetic do I have to stay with a synthetic oil?
All of Castrol’s oils are fully compatible with one another, and there is no cause for concern if you choose to switch from conventional to synthetic or vice versa. Because of this, it is not necessary to flush the engine. It is a common myth that you cannot go back to conventional motor oil after using synthetic.
Even if you’ve switched to premium synthetic motor oil like Castrol Syntec, you can always go back to conventional oil, but why would you want to? Consider Castrol Syntec Full-Synthetic motor oil a “super lubricant,” as it seeks out and neutralizes harmful particles in your engine, fights sludge on vital engine parts, neutralizes acids in your engine, and is fully compatible with conventional motor oil. For example, Castrol Syntec actually engulfs particles preventing them from grouping together and forming engine sludge. Synthetic motor oils deliver superior engine protection versus conventional oils, and once you try it, while you can go back, we doubt you’ll want to.
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