I have a 2003 3.7 that had in a real cold start up -5 below through a rocker arm this past March. 2 weeks ago it started a small tapping noise. I ran seafoam through it and it went away in five minutes. I ran it for 60 or so miles with it in the engine and it starting kncking real loud. I had the oil changed immedialtely and the noise was still there but not as bad. I drove the truck home and was loud again. I have pulled the valve cover off and the rocker arms seem to be tarnished a brown color like varnish on metal on the number 2 cylinder. The other four rockers are a black in color. I started the vehicle and it seems that no oil is coming from the lash adjusters. Have they collapsed, and could this have been the problem that caused this same rocker to come off in March.

Looking for an answer before proceeding to tear out the adjusters.

Thanks Ray