I have a 94 6.5 TD and fuel is leaking from the valley to the drain in the block. It comes and goes. All the return lines are weather cracked and the metal lines are very rusty. Any ideas where else it could be coming from.?

Check your filter manager for leaks. The bottom of the manager where the wires come out is where some leaks have been found. Also the supply line from the manager to the IP gets old and cracked. The line from the manager to the t-valve can get cracks in it also. Check your clamps on the manager. I found my clamps were loose and caused some leaks.