2010 Camry Strange sound Need help
 

Hello,
My wife's 2010 Camry 2.5 L4 is making a strange sound, I thought it was idling rough so I changed the spark plugs, (found oil ABOVE plug number 2 not inside the cylinder but above the plug, I am thinking the Valve cover gasket is bad? Anyway the sound is still there, I thought it was a knocking sound but it kinda sounds like it coming from the belt sides maybe a bearing or something? If anyone has any suggestions let me know. Video to sound below. Thanks in advanced!

At around 27 seconds the rattle comes out. Might be a bearing. An alternator or idler pulley bearing for a belt. Hold hose near both ends of alternator and a near belt idlers.