PeachParts Mercedes-Benz Forum - View Single Post

2.5Turbo · #5 12-09-2013, 05:15 PM

I picked one up last summer. It has the 642 engine and the NAG1/W5A580 transmission which was DC's name for the 722.6.

Common problems:

Swirl motor. (DTC P2015) The motor that moves the intake port flaps to change intake runner lengths. The PCV vent seal leaks oil where it goes into the intake right before the turbo. The oil drips right down on the motor and causes it to fail. Very expensive dealer repair as most of the time they charge you for a new intake manifold since it is extremely difficult to not break the linkage when replacing the motor. I believe the FSM requires pulling the motor to do this repair. The swirl valve system is there primarily for emissions and can be bypassed by inserting a certain value resistor in the plug to the motor. The Green Diesel Engineering tune also disables the swirl motor as well as its proving programming in the computer. GDE tune also disables the EGR and provides better performance and MPG.

Leaky intake seals. As mentioned previously, the seal between the PCV pipe and the intake pipe leaks. The original seal is orange and the updated one is black. The seal unfortunately is unavailable on its own so you must buy the whole intake tube, about $80. Alternative is to rig up an "elephant hose" to vent PCV gas to a catch can or to under the car. This prevents leak problems and also keeps oil from clogging up your intercooler and intake.

Crankshaft position sensor. MB put out a TSB on this issue for early 2007 vehicles. A bad run of crank position sensors functioned intermittently. It would cause the vehicle to stall and/or not start. Since the computer needs to know crank angle to time the injections it won't run without it.

The GDE tune is highly recommended as it takes care of a number of issues as well as disabling the EGR...we all know what that does mixed with blowby gasses. I don't have it yet but many on the Jeep forums do and everyone loves it.

I get 23-24mpg on the highway. GDE gains you about 2-3 more MPG by reducing pre and post injection events mainly there to quiet combustion noise. If you don't care about your diesel sounding like a diesel, go for the tune.

Towing with this rig is amazing; it's rated to 7200lbs. I pulled a 3500lb travel trailer this summer and it didn't break a sweat. Towing MPG is almost better than gasser MPG when they aren't towing!

Mine is currently in the shop for transmission or transfer case work...before I bought it both the transmission and transfer case were replaced by the PO by his warranty. PO was out of town and repair was taking too long so he just traded it in for a new GC. 6000 miles later I'm getting intermittent grinding and loss of power. Sounds like it's coming from the t-case. 12 month, 12k mile parts and service warranty should be taking care of it.