If your refering this, its more a question.Has anyone changed the fuel filter (not water separator) every other change out, due to the water separator keeping the primary filter clean?
This statement was enough for me to change both, being the front filter has better filtration then the first filter.I change both fuel filters around 13k miles. You probably won't see anything on the engine mounted filter because it is mostly to remove the very small particulates--it is a Nanonet filter. It still should be changed every 15k or more often. I put a foot long piece of 1/2" copper tubing into the front factory drain hose, and 1/2" clear tubing on the nipple of the rear filter's water separator. The front tubing will be just in front of the front differential cover.