New answers tagged

4

Sometimes it is hard to tell the difference between a rod knock, wrist pin or piston slap in the early stages even when using a mechanics stethoscope. A main knock is a deeper sound that is more pronounced at the bottom of the block as apposed to the top when using a stethoscope. Hard knocks that happen at startup and go away quickly are a sure sign it is ...


7

When you start the engine and you hear the sound, does it sound better after the vehicle is warmed up? A rod knock will only sound worse (louder) as the engine heats up. It will not go away as the engine gets warmer. If it does, it is probably something like an exhaust leak which closes itself as the engine manifolds get warm. The opposite could be true as ...



Top 50 recent answers are included