I've searched and haven't found a similar problem, so I'm posting new.

My 2005 E320CDI experienced a fuel leak last week. Difficult to see initially, due to all the plastic shields underneath the car holding the fuel and letting it go at various times and from various spots.

I determined that the return line hose came loose from the barb on the #2 injector. The fuel collects in the injector area, and routes it to the rear of the engine, then drops it onto the bellhousing/starter area.

Assuming the return hoses may be tired after 257K, I replaced all the short injector return lines with MB dealer hose.

A short test drive showed success. An extended test drive had fuel leaking again. I found one of the new injector return lines came loose at an injector.

I'm assuming that the injector lines are seeing excessive pressure, especially since these are designed with no clamps, just hose pushed over a barb.

The return line to the tank collects fuel from three places...injectors, back of the fuel rail, and from the HP pump as well. Breaking the circuits shows no excessive pressure or flow from either injectors or back of fuel rail. The line from the HP pump has significant flow. I attached a pressure gauge and read about 7psi with all lines connected.

Is 7psi correct? Would that indicate some blockage in the return line between there and the tank? I blew the line with compressed air from engine area to tank, and it seems clear, but any details or info is welcome please.

Thanks

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Mark in MA
05 MB E320CDI 402k Granite Grey Metallic
05 MB E320CDI 267k Black
05 MB E320CDI 232k White
05 MB E320CDI 209k Tectite Grey
99 Dodge 2500 Cummins 5sp 148k
62 Jeep CJ-6 120k