Synthetic oil, can I mix with regular oil, and can I add synthetic oil to exist oil in my car?
no it is not recommended plus it will froth up in the engine you either run regular oil or synthetic oil and they say if you put synthetic oil in your engine its not good to convert back to regular oil
You can but you should change your oil soon it's not good to mix them because they're different formulas regular oil burns faster
Do not mix them together. It won't hurt anything but why not drain the oil in the car now before adding any type of new oil.