My car won't start and when it does it has a knock in the motor.
It sounds like your engine may be seizing up due to low oil. I would first recommend checking the engine oil to ensure its proper level. If the oil is low this could be your problem. If the engine is not seizing up and the no start is related to something else, the other causes may be fuel, ignition, or starting system issues. The knock could be a separate issue but still likely due to running low on oil at some point or being low on oil currently. I would recommend having a technician from YourMechanic come inspect all of the systems on your vehicle to determine if replacement of the engine, battery, starter, fuel system parts, or otherwise is needed.
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