Propane question

[Allen in MT]

Both of my tanks are full and have been emptied and refilled thru normal use and still my indicator reads about 1/2 to 3/4 red all the time, The indicator will go completely red when empty. I think I need to replace the valve, was told that if they stick might give a shot od wd40 into one port, but not sure of doing that, might be simpler to just replace to be sure
Allen