Need some 7.3 filter head check valve advise

[The_Josh_Bear]

Even more effective is to just use an in-line check valve rated for diesel, such as:


Amazon check valves

Now I'm not suggesting these exact valves, but something like it. I rekon you'd want something 1/4" for the 89+ return system. That's what I've used for many years and it works well. Cheaper and much more reliable than either of the Ford/IH designs.

You must be registered for see images attach

 

[Bart F-350]

That could be logic if you are sure for the function/direction of the fluid.
To me what I read here in this post is more gestimate what and where diesel or air should do????

I was thinking (seeing only a small hole in my brass fitting on that same spot) that this was ford's form of reducing flow/keeping enough pressure on the return lines, I know that sustem from VW and several agricultural tractors.

so, what would be the true reason for that assy?

 

[The_Josh_Bear]

We don't want return line pressure. This check valve is just to give air a place to escape before it gets into the IP. I've switched away from the stock fuel header and ran a system without an air return for a while. I added it back in later with a check valve like I posted above and it's miles ahead in air problem solving.
If you're too slow to switch tanks going up a hill you get huge amounts of air in the IP without the air returning to the tank. Same situation with the air return and it hiccups, might stall, but the IP is generally full of fuel still and starts just fine. HUGE difference.
These check valves also don't leak like the OEM ones do and cause fuel drain-back, which causes hard starts.