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Q: Changing oil grades without flushing

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Can you change engine oil grades from 10-40 to 20-40 without flush?

A: Sure, all oil is mixable. You can mix synth...

Sure, all oil is mixable. You can mix synthetic and non-synthetic oil, too. You’ll just want to take most of the oil out when you change it and what is left is mixable. It won’t hurt anything.

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