GregSoDak

Replaced entire ac system, after driving for a few miles began to notice a slight noise, then growing louder. Sounded like bearing rubbing on each rotation of the crank. Process of elimination, took serpentine belt off, same; then ac belt off, noise continued. Based on my "screwdriver stethoscope" it is loadest at the timing chain cover, dissapating the farther back on the oil pan I go. Possible harmonic balancer, oil pump/oil pump o-ring at pick-up tube (doubtful since there is no change to the oil pressure), timing chain, or something else? Any suggestions before I begin the replacement of all?