I was smelling diesel but could not find the leak over an extended period of time. Nothing dirty around the filter. Nothing and bone dry around the injectors and glow plugs. While I have had problems with the pressure control valve, it was all dry to touch (since you really can't see it). But the front of the engine was getting more and more dirty and constantly wet. But (I discovered since) not all of that was related to diesel - as there was a leak of coolant on the water pump return that only leaked when the engine was hot and the system under pressure. Further, I wrapped some of the clear fuel lines with paper to see if I could isolate the leaking line. But you can only go so far with this technique - and the all the paper stayed dry. Both pumps appeared dry. So I proceeded to change out the 3 clear fuel lines. This is only applicable to OM612 engines.
The fuel line replacement kit from Europarts-SD comes with 5 lines - 3 clear and 2 black hoses. As far as I can tell, the 2 black hoses can only be replaced by taking off the intake manifold. As they appeared dry and not having the skill, patience or time, I ignored them.
In the poorly drawn diagram below as shown 3 lines -
RED - the supply line from the fuel filter to the low pressure pump
BLACK - the 3-armed line. The supply line from the low pressure pump to the high pressure pump and to an unknown purpose line under the intake manifold (maybe a supply to a post-rail cavity of some type?)
BLUE - the supply line to the back of the rail
RED line: By far the easiest line to replace. To get working room, disconnect the top intercooler hose, top 2 radiator hoses and the vacuum line crossing in front of the low pressure pump. There are several clips that hold the line in place. However, the one(s) inside the intake manifold cavity are basically unreachable. The ones near the front of the engine are heat, age and chemical compromised and break immediately. Both ends are Voss connectors. That means push the white arms in until they lock in place, then pull off. If the first time, they will be hard to pull off. Fish the new line back through the intake manifold cavity, silicone grease the Voss connectors, and re-attach.
Because of the broken connectors and the ones that you cannot get to, use zip ties where you can, and use loom protectors for the areas that you cannot so that friction and vibration don't cause a hole in the new fuel line. The picture below shows one of the zips I used and the red loom in the back protecting the line as it comes out from under the manifold.
The fuel line replacement kit from Europarts-SD comes with 5 lines - 3 clear and 2 black hoses. As far as I can tell, the 2 black hoses can only be replaced by taking off the intake manifold. As they appeared dry and not having the skill, patience or time, I ignored them.
In the poorly drawn diagram below as shown 3 lines -
RED - the supply line from the fuel filter to the low pressure pump
BLACK - the 3-armed line. The supply line from the low pressure pump to the high pressure pump and to an unknown purpose line under the intake manifold (maybe a supply to a post-rail cavity of some type?)
BLUE - the supply line to the back of the rail
RED line: By far the easiest line to replace. To get working room, disconnect the top intercooler hose, top 2 radiator hoses and the vacuum line crossing in front of the low pressure pump. There are several clips that hold the line in place. However, the one(s) inside the intake manifold cavity are basically unreachable. The ones near the front of the engine are heat, age and chemical compromised and break immediately. Both ends are Voss connectors. That means push the white arms in until they lock in place, then pull off. If the first time, they will be hard to pull off. Fish the new line back through the intake manifold cavity, silicone grease the Voss connectors, and re-attach.
Because of the broken connectors and the ones that you cannot get to, use zip ties where you can, and use loom protectors for the areas that you cannot so that friction and vibration don't cause a hole in the new fuel line. The picture below shows one of the zips I used and the red loom in the back protecting the line as it comes out from under the manifold.
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