This article relates to the late model Jeep Grand Cherokee fitted with a OM642 Engine
Throughout the early 2000’s Jeep (MOPAR) and Mercedes Benz had a partnership that resulted in the “cross pollination” of some vehicles the Grand Cherokees that came out in that era with s 3.0 V6 Diesel engine actually had a Mercedes Benz engine that was also fitted so some of the Mercedes ML vehicles.
One of the common faults with this motor is a hard to start issue when the vehicle is cold.
This issues is not a fault on the current 3.0 diesel V6’s made by Chrysler.
The most common cause of this hard to start issue is faulty glow plugs and or the glow plug module. The easiest way to get to the bottom of this is a simple code scan. When either of these parts give trouble they normally log fault codes but won’t always bring on the check engine light.
In our experience always replace all 6 glow plugs and the module together. Yes it can be expensive but if one or more of these parts are faulty they can cause the others to be damaged.
Jeep charges a ludicrous amount of money for these. Here is a trick for new players. Take the Jeep part number off the module (its mounted upside down at the very front of the engine. See the image for reference.) and get a quote of Mercedes Benz.
At the time of writing this Jeep quoted over $800 for the module and Mercedes Benz around $200 (Australian Dollars) they are identical parts and the Mercedes Benz part will work on the Jeep.