Q: Engine knock at startup

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My car 2004 Chevrolet Classic with 193,000 miles on it started knocking. I parked it. The radiator reservoir was empty so I filled it. Cranked the car and the sound began to quiet bit did nit go away. Now when the car is started it knocks hard for a second at startup then dulls to barely noticeable. It knocks more noticeable in reverse. Oil was changed after the knock began as well. What could cause this?

My car has 193000 miles.
My car has an automatic transmission.

Hello there. In most cases, an engine knocking sound at start up is caused by hardware inside the cylinder head of the motor that is loose or is not properly lubricated. As the engine starts, and oil is circulated to the top of the motor, the knocking will subside. This type of noise can also be caused by a loose belt or pulley. As such, it is probably best to have a professional mechanic come to your location and complete a car is making a noise inspection, so they can determine what is causing this noise.

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