Mercedes-Benz Sprinter vans have proven to be reliable workhorses. Like any vehicle, however, they have a few known issues that can arise after being on the road for 10+ years. We’ve experienced these repairs firsthand and wanted to highlight 5 common failures to help you stay out of limp mode.
#1 Broken Swirl Rods
The OM642 engine is a diesel engine that utilizes swirl flaps on the intake manifolds, operated by plastic swirl rods. These allow for the electronic control of airflow. By controlling the airflow with the flaps, there is a greater ability to regulate the fuel-to-air ratio. This aids in emissions and improves low-end torque.
Over time, these flaps can stick due to buildup of carbon and oil from the breather system. The movement of these flaps is controlled by a motor, which has plastic arms that connect to the manifold. The plastic can become brittle over time due to heating and cooling cycles. Mercedes does not offer these as a replacement, instead only offering the entire manifold. There are now upgraded metal swirl rods that can be used to replace the old plastic version. The metal rods are a direct replacement for the plastic ones. The first step should be to clean the intake manifold to be sure the flaps are moving freely.
#2 Oil Cooler Seal Leaks
A common failure on the OM642 engine is the oil cooler seals. A sign of the oil cooler seal failing will appear with signs you would expect from a typical oil leak. Such as low oil level warnings or oil stains under the vehicle. When replacing the seals, make sure you are buying the most updated oil cooler seals: the purple Viton seals with the part number 6421880580.
Because the oil cooler sits at the bottom and middle of the V shape of the engine, you’ll need a full oil cooler seal kit, as there are lots of one-time-use seals that should be replaced. Since you need to remove the intake manifolds for this job, it’s a good opportunity to clean the manifolds and the swirl flaps.
#3 Limp Mode After Oil Cooler Seals
If you are experiencing limp mode after replacing the oil cooler seals on your OM642 Sprinter Van, the good news is that it is probably an easy fix. The ECU will show codes for the MAFs and IAT sensors, potentially more. The first thing to know is that codes that cannot be cleared or reappear immediately, even with the engine off, are an indication that the sensors are no longer connected. First, check that all connectors are properly seated – the Mercedes connectors need to be fully seated and “CLICK” into place, or else they will not get a good signal.
If you are certain the connectors are fully seated, then you probably blew the fuse that these sensors all get power from, especially if you did not disconnect the battery before starting the job. The fuse that powers all these sensors is located in the fuse box under the hood. If you pull that fuse, you will see that it has blown – e.g. the wire inside the fuse has broken. Get a replacement 15A fuse. Do not put a higher-amp fuse in that location. Fuse amperage is carefully chosen by the engineers designing the electrical system. Fuses blow to protect other electrical components. Putting in a higher amp fuse can expose more expensive components & wires to currents they cannot handle.
#4 Failed Intake Seals
A common problem in Sprinters is faulty seals on your air intake pipe. These can be the most common reason for low power, limp mode, and check engine lights. These seals are a cheap and quick fix that can save you costly repairs down the road. A faulty turbocharger inlet seal can allow dirty air into your turbo, which can shorten the life of your turbo. Likewise a failure in the seal where the CCV connects can also allow dirty air into your turbo. Another seal failure can occur at the outlet pipe. A failed seal will allow oil to spray out when the air is moving through the pipe. It is likely there will be a smell of oil in the cabin if these seals have failed.
#5 Injector Black Death
Injector “Black Death” is when the seal under your injector fails. This causes exhaust fumes to leak. When it escapes, it carbonizes and builds up as gunk in the engine, leading to hard starting and decreased fuel economy. For obvious reasons, this is not good for your vehicle’s engine. It is important to make sure when you complete this job that you use a new bolt with the new seal. Since the bolts are stretch-to-yield, an old bolt will not properly seal and you’ll just be setting yourself up to do the job all over. The injector removal claw and a slide hammer are essential tools to make the removal quicker as well as not damaging the aluminum valve cover.
Relevant Kits & Special Tools:
Full set of replacement seals to complete an oil cooler seal replacement. Includes all gaskets and seals for the items that must be removed in order to access the oil cooler.
Replacing this seal requires removing many components on the engine, which each have seals of their own that must be replaced. We highly recommend purchasing the OM642 Oil Cooler Seal Kit instead of individual seals.
Injector Install Kit (OM642)(OM648)
All these items *MUST* be replaced whenever removing and installing injectors.
We recommending refreshing the seals and bolts every 100,000 miles to avoid leaks.
OM642 Early – Upgraded Metal Swirl Rod Repair Kit
MADE IN CANADA. Includes upgraded bushings. These are not the cheap Chinese versions.
Intended for 2006 – 2009 models.
OM642 Late – Upgraded Metal Swirl Rod Repair Kit
Set of custom made replacement metal swirl flap rods and new bushings for the intake manifolds on the 2010+ Sprinter Van and all Mercedes models with the 3.0L Mercedes V6 diesel engine, code OM642.
OEM Number: 00000000765164
