Were you able to make the 2019 oil filler tube work for your 2016 5.3? I've searched all over and can't verify it. I just changed oil yesterday and went through 4 different funnels, two flex, two regular, a measuring cup, and tried to hit the hole with a 5qt Mobil 1 bottle?. The flex went in the hole but was so slow it took 20 minutes to get 8 quarts in. Ridiculous! A job that used to take 10 minutes now takes 30 minutes by the time you dribble oil in at a snail's pace then clean everything up trying multiple devices, drips, runs, etc. WTF were they thinking? I don't want to have to carve something out with a Dremel, but may have to. Anybody else have any luck with the one mentioned?
Having just posted that, just saw the newest posts about it working. Great news!