Fuel line question...cat 112 motor grader

With all your help a year ago, we got our "new" 1952 Cat 112 motor grader operating. Serial 3U3844. it's got the d315 engine in . I've spent almost 50 hours on the machine in the last year. Slowly getting used to operating and am making a difference on our 2 miles of road.

My question for the membership here is this: out of the bottom of the fuel pump/filter area are two fuel lines that just dead end at the bottom of the engine near the level of the oil pan. While the engine is operating, diesel slowly leaks out. It's not a lot of fuel....maybe a quart over three hours of operation. And when the engine shuts down, there's an even slower leak. I slid plastic hose over the lines and collect the leaking diesel instead of dripping it on the ground. The parts/engine book doesn't show if these lines go elsewhere or if they're supposed to be plugged, or????

Is this situation normal for this engine or should those lines be capped/sealed? Thanks for reading and any insight you can provide.

[attachment=34565]D315_fuel_side.jpg[/attachment] [attachment=34566]d315_line_end.jpg[/attachment]

Do not cap them. They are there to drain fuel away from places where it will mix with lube oil and ruin the lubricity of that oil so parts get damaged.

Most engines have one from the upper fuel filter vent valve. This should not leak, but sometimes the valve gets scored or gets rust etc in it. Might need to replace or lap the seat and plunger to get it to seal properly.

Then there is a line draining the fuel injection pump area to keep the small amount of leakage from the pump plungers that keeps them lubricated from spilling over into the sump where the oil is that lubes the camshaft and lifters. You might have a worn pump that is leaking most of that volume that you could replace. This should be obvious when you look in the inspection cover on the side of the pump housing.

The third source is a telltale drain from the seal cavity of the fuel lift/transfer pump drive shaft. This is to prevent fuel from getting into the engine oil and usually works just fine. Almost always when you get fuel in the oil pan it comes from a bad seal between fuel filter tower and injection pump housing, not from the lift pump shaft seal cavity. The telltale is a big part of the reason this area is seldom the source.

Thanks, ccjersey....

i was hoping it was cooling or lubrication. and it sounds like the amount of leakage at this time is not significant. And now i have more to investigate and fix. no fuel in the oil yet. i've read here on the forum about those seals replacement.

Doug