Paccar fuel filter doesn't stay full

[aaronb]

(02-24-2018 )Pete379 Wrote:  I have that same filter setup. The paccar filter assembly mounted vertically on the frame should be full of fuel to the top. Pull the filter and take a look where the pickup is at. It looks like it would be right at the level that your fuel is so that would explain why no hard starts it’s getting fuel but there’s something wrong. Possibly a check valve or something. I never experienced this problem but you have to address it. Does it look like that while the engine in running or only when it is off?

The engine was running when I took that picture. I've had the filter off and looked up at the housing. There's a hole in the top of the cartridge with a plastic pin that pushes open the valve in the top of the housing to let fuel through. The fuel pickup in the housing is at the top. That's why I was thinking the housing base is bad and is somehow bypassing the filter. I don't know how else the truck could run if the fuel level is like 6 inches below the pickup where it's supposed to flow out of the filter.