Mine had a stubborn air leak that showed up on it's maiden voyage home from the dealer in May of 2006
Since it was not a constant problem and dealers knew little about our CRD I got the "could not duplicate" rubber stamp
Others were having the same problem and I installed one under the hood using Black Liberty's methode to verify air in the fuel was the problem, there were two problems that caused similiar symptoms pre f37
I considered under the hood faucit pump a test or a temporary solution
About that time I installed trailer wiring and discovered a "prime pump" relay and fuse already in the power distribution box in front of the battery
Another traced the wire to under the rear seat

Yet another, maybe GMCTD, discovered the pump from a Cummins powered Dodge fit our application
So for many that was a clear sign of what should have been
Air was the problem and the jeep ran much better so I installed a intank lift pump and have never looked back. That was 6 years ago
It sure makes filter replacement easy
Some think the new style fuel head is a cure all for air in the fuel
Others look further and view the fuel head as a victim of another problem and cure that problem instead, yeah if it's melted it needs replaced
If you keep the air from building up in the filter head it will not overheat and then leak. I still have my original fuel head
