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Q: Knocking noise under hood

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When the car cranks and while running, there is a knocking noise that comes from under the hood.

My car has 100000 miles.
My car has an automatic transmission.

Without actually hearing the noise, it is difficult to determine the exact cause of your concern. It could be low oil pressure, valve adjustment, bearing failure, etc. I suggest having a certified technician, like one from YourMechanic, determine the exact cause the noise.

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