Started my Suburban today and got a knocking tapping sound from up high in the engine. This is not the cold start sound that goes away. This is slightly louder, in sync with RPM's. No drop in oil pressure. Has 135K miles. Any insight as I am trying to get idea of what it might be and the potential cost.
Thanks

 

Possibly anything in the valvetrain. Loose rocker, bent valve, bent push rod, valve lash could need to be adjusted going back to the loose rocker, could be a lifter. A knock in the bottom end is easier to narrow down for you .