That is one of three causes, including a 4th less common cause of lifters. The business about the lifters is when they knock it is usually at start up so when the lube coats it they quite down, the other ticks are more serious.
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The Hemi has a very short skirt and thin rings with virtually no land area, the piston wants to rock in the bores. This is another reason for the moly piston skirt coatings. It is designed to cushion the short skirt. The problem is that as miles rack up, the moly is worn off and a louder engine or tapping noise begins to occur. This is the third part of the Hemi Tick. This part actually contributes to more aluminum in your oil analysis. An oil analysis is always important to do on any engine you want to take care of as a baseline, and then every 3rd oil change, do one just to be sure nothing is leaking or causing problems.
