I can't count the number of times i have heard an engine with a knock but what exactly does this mean? What is causing it to make this noise. I started caring because my engine is knocking and I'm a little worried. How long does the engine have left? Is there anything non expensive I can do to help the problem? Thanks in advance for any insight that you might be able to share with me.

 

check your oil level. could be valves with to much play in them, or if its coming from the bottom end its a rod prolly. bad bearings.