They are kind of both unit and common rail. Remember the series 55 detroits? The MB's have a high pressure pump that sends fuel to cam driven unit injectors on the side of the block. These act like an injection pump for each cylinder and are electronically driven. The fuel then goes thru a jumper line. It basically is a small fuel line about 4" line that is shaped like an S. This line attaches to the top of the unit pump and the other end attaches to a transfer tube almost identical to an ISB. The fuel then goes to the mechanical injector that is identical in looks to the ISB injector. You probably wont be able to see any of the fuel lines or unit pumps since they are covered up by the black plastic panel on the drivers side of the engine, but are very easy to change out. Unit pump is held into the head by 2 bolts, the jumper lines are screw on and are external. Just removing the trim cover is all that is involved to get to it.

The EGR coolers arent bad at all. Drain the coolant, remove the air filter and then the cooler. I think book time is 1.9 hours. Price for the cooler is around a grand.

 

Cool...so it sounds like those engines are thought out to be halfway simple to work on. I wish I could say the same for the Chevy...open the hood on it and you can't even see the engine

Thanks Again Monty! I don't think I have any more questions for now...but I'm gonna try and go check out a couple trucks this weekend! I'll be back Monday with more questions probably

Chris