Alright i'm playing around with the FP gauge, wondering how much of a drop in pressure is &quot;acceptable&quot; before needing a filter change. Don't remember the numbers off hand but there was a 1-2 psi difference (lower on the post filter side, obviously). I'm going to change the filter soon anyways, just wondering if there was a certain pressure drop that was okay or not okay. TIA<br><br>BTW this is a 98.5, taking both readings from top of filter housing.

 

For what it is worth the Dodge service manual allows for up to a 5psi drop across the filter.

 

I have a 98.5 my guage is post filter my opion is to check it WOT it is not supposed to be below 8. Mine idles at 15 and my filter has around 6k on it. You also might want to check out your dipstick on some 98.5 the reading is wrong by 1.5 quarts too much. I believe if you go to www. dodgeram.org it will give you the right and wrong numbers. Mine had the incorrect stick on it

 

Yeah I checked it both pre and post filter today just for the heck of it. It only varied by maybe 1 psi, not much. Anyways i've got around 12 idle, 10 cruise, and 9 or 10 WOT. So basically it's on the verge of needing replaced so i'm keeping an eye on it till I get to Cummins to pick up a new pump. Thanks for the help guys.