Q: Knocking from the motor

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When I start my truck, there is a loud knock coming from the motor

My car has 182000 miles.
My car has an automatic transmission.

Hi. The usual cause of the loud knocking in these motors are one of two things (or both). The timing chain guides become loose or worn out and sometimes causes the engine to knock or tick when it is running. The other possible cause of your knock is there are worn out internal engine parts in the engine block. For example the piston bearings are worn-out, the crankshaft is worn-out, or the piston ring has broken or is worn out causing the noise. If the timing chain is the problem that can be fixed without replacing the engine. If you have any of the other parts that I mentioned causing the issue, then the engine will have to be replaced or rebuilt. A professional technician from YourMechanic can come to your car’s location to inspect the engine noise and advise you on the correct repairs.

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