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Q: Mixing engine oil causes light knocking in the engine. Should the oil be changed immediately?

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mixing engine oil accidentally(10w-30 and 10w-40) causes light engine knocking. It started about 3 weeks ago, should I change oil immediately ?

My car has 66000 miles.
My car has an automatic transmission.

A: If you are using too thick of an oil, the e...

If you are using too thick of an oil, the engine may not be properly lubricated. The oil should be changed as soon as possible. If the engine was previously low on oil, topped off with additional oil, and noise persists, the engine's internal bearings may have been damaged. Have the oil and filter changed, put in the correct oil, and see if noise continues. If it does, a YourMechanic professional can help you check the engine for bearing damage.

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