Probably the timing chain tensioner...very common...most folks say it sounds like a desiel. Costs about $130 and takes 10min to install.

 

no sense in guessing engine noise over the net, the least we will need is a video with good sound to even start guessing what noise he has. Don't want to give this person the wrong info and have him tear his car apart for no reason. This could be as easily as an idler pulley up to a rod knock.

Get us a video with decent sound if want accurate info.