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Q: Why is my engine knocking?

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Making a loud knocking sounds had ran out of oil put 5qts of oil in and it's still knocking, what may it be?

My car has 107000 miles.
My car has an automatic transmission.

A: A loud knocking noise coming from the engin...

A loud knocking noise coming from the engine can be any of several issues. Having to put 5 quarts of oil in the engine means that the engine was completely empty, basically. The engine oil's main purpose is lubrication, and without that lubrication, this can lead to any number of problems inside the engine. The lack of oil will cause incredible friction between the moving parts, which can cause bent connecting rods, failed crankshaft or connecting rod bearings, stretched connecting rod caps, spun bearings, or any number of other catastrophic failures within the engine. The only way to find out exactly what has failed is to have a certified mechanic, like those available at YourMechanic.com, to take a look at the vehicle and do some diagnostics.

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