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Q: Knocking noise coming from engine

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Ok my car has a loud knocking noise coming from it I was told I need a new engine

My car has 179000 miles.
My car has an automatic transmission.

A: Hi and thanks for contacting YourMechanic. ...

Hi and thanks for contacting YourMechanic. If the engine runs okay and has a little vibration with a loud knocking noise, and the oil pressure is low at idle and high when above idle, then you have a rod knocking from a failed or burned rod bearing. If this is the case, drain out the oil and remove the oil pan; then remove the rod bearings from the rods - I recommend replacing all of the rod bearings, even if they don’t look that bad. The bearings can be replaced with the engine still in the car. Once you have replaced all of the rod bearings, make sure that you torque all of the rod bolts or nuts to the manufactures build specs. Then put the oil pan on with a new pan gasket and a new oil filter. Put in new oil in the engine and start the engine. If the knock goes away they the problem is fixed.

If the knock continues, then you have a piston that is coming apart and needs replacing. If the engine has a vibration afterwards but there is no knock, then the valve train on the cylinder heads are bent and causing a minor misfire.

Problems with engine noise can be symptoms of serious issues, so a certified YourMechanic technician can be dispatched to your location to inspect your engine knocking and provide you with a second opinion or assist you with any repairs.

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