jczunega

sounds like the pistons. could the cylinder walls be worn? or normal. when running the engine at first while at cold temperature there's a clearance/gap between the piston sides and cylinder walls to give way for the pistons thermal expansion at normal operating temperature which would cause the piston to dance hitting the cylinder walls causing the rattling noise but as it gets hotter it expands more until that clearance is no more causing the sound gone and making the engine run smoothly. i think it's normal but if the noise is excessive it could be worn or something.