So I have replaced every seal on this motor other than the rear main. Luckily have stopped my leaks for now. Jeep runs really good and doesn't show signs of any major problems. The valve covers and heads were spotless. However, I noticed quite a bit of varnish on the upper case pan and around the timing cover inside the block. Does that seem normal? 3k OCI'S with Valvoline full synthetic. Would a oil like Royal Purple or Redline be better?