I am going to be changing my fuel filter sometime soon on my 86 300E. On our farm here, anytime we change fuel filters on any diesel equipment, we make sure to use the hand pump on the injector pump so as to get the filter full of fuel, and usually leave them loose to get the air out of them. There are usually a couple of filters mounted on the side of the big 855 cid diesel engines, along with a glass water filter.
So, after changing the filter on the car, the fuel filter is going to be full of air until the electric pump fills it up, although I would think that volume of air is going to stay somewhere until it is expelled from the lines somehow. Does this air then get into the injector pump and then cause hard starting problems or terrible running until the air is gone? Does anybody bleed the fuel lines? Or am I making a mountain out of a molehill? Thanks