I bought a 2004 Chrysler Pacifica 3.5 L when I test drove it the engine sounded great no knocking sound at all. About 4 days later when I started it there is a loud knocking coming from the engine I checked the oil and its not low, from what Ive read on lots of these forums that it can be the rocker arms assembly that causes it. My Question is first how can I make sure it is the rocker arms ? and Is It safe to drive it ticking like that ? hope someone can help me with this thanks..