I have Japanese Alto 660cc 2011 model. My car has been giving a rattling sound. One Mechanic told me that its knocking problem due to low quality fuel and other told me it's tappet and another told me that I have to get the gear oil changed. So it's quite confusing. I changed the spark plug and got full throttle body service. But sound is still there. I feel it's a tappet problem rather than engine knocking. Can anyone guide me where to get its tappet checked. And what's the maintenance of tappet? Does Mechanic simply change the shims?
Car's pick is good. This problem hasn't hurt the engine performance.