so i adjusted the valves on my sisters car, put in new plugs, new valve cover seals, spark plug seals, and new seals for the valve cover bolts ect, did a nice job. anyhow, when i removed the front valve cover, everything was spotless. nice. when i removed the rear one, everything was coated in varnish...very very thin layer that made everything look brown. wasnt that super baked on stuff though, you could get to shiny metal rubbing with your finger pretty easily. i washed out the valve covers before reinstall to remove any grit, and even w/ a nylon brush and reg soap that varnish stuff came off pretty easily.

Oil is changed every 3-4k miles w/ factory filter, always dino oil, either castrol GTX or chevron supreame. the car is usually driven 40/60 city highway, and isnt really beat on at all. just regular driving.


SO is this common? only thing myself and my buddy could think of, was that it was a heat thing, where the front head ran cooler than the one in the back hence the lack of any build up on the front, but varnish on the back head?

Let me know your thoughts/experiences!