OM642 - V6 DIESEL ENGINE ROBUST ENOUGH OR TICKING TIME BOMB?

The OM642 engine, a diesel engine known for its technical finesse as well as its weaknesses, poses a real challenge for many of its vehicle owners after a certain mileage.

1.) One of the most frequently discussed issues concerns the leaks at the seals of the Heat exchangers and the accompanying dramatic consequential errors. This specific vulnerability leads to significant costs, as the replacement of these so-called "penny seals" requires extensive preparation and the heat exchanger (oil cooler) is not easily accessible. For this reason, many vehicle owners prefer to tolerate a few oil stains on the underbody protection rather than fix the leaks in the oil cooler. Ignoring the correct procedure for this repair has fatal consequences.

2.) The OM642 engine uses a Bosch common rail fuel system, which is known for its performance. However, the components used Piezo injectors high demands on the quality of diesel fuel, which makes them quite susceptible to wear. A defective injector has a direct impact on the components of the engine mechanics of the OM642. The pistons can melt or even break under the influence of poorly atomized fuel. If fuel gets into the oil, it becomes heavily diluted and can no longer guarantee its lubricating properties. The result is often a major engine failure, as we will discuss in the course of this article.

3.) Another weak point of the OM642 engine is the Fuel quantity control valve In the injection pump, which has a tendency to regular failures. The replacement is simple and a malfunction usually does not lead to consequential damage, as the uneven engine running and the storage of errors in the error memory are noticed early and a repair can be initiated.

4.) Often unnoticed is the pollution of the Swirl flaps, which are located within the charge air distributors. The exhaust gas recirculation system (EGR) supplies cooled exhaust gases to the charge pressure distributors and later to the combustion process. This system is essential for compliance with exhaust emission regulations. The recirculated exhaust gases contain large amounts of soot particles, which accumulate in the form of oil carbon on the surface of the charge pressure distributors. These contaminants regularly lead to malfunctions of the swirl flaps, which are indispensable for the torque curve of the engine. Consequently, the OM642 engine loses power or can be severely damaged by dislodged oil carbon particles. The regular cleaning of these components is - like many maintenance tasks - unfortunately not included in the inspection interval of the OM642. We will change that!

5.) Regarding the Turbochargers a robust Garrett turbine is installed, which typically operates for up to 300,000 kilometers without noticeable noise, provided that the necessary lubrication and cooling of the component are ensured. The variable turbine geometry (VTG) system can become blocked due to heavy contamination. A common cause of damage to the OM642 turbine is collisions with particles, as well as lubrication failure due to insufficient oil pressure or poor oil quality.

6.) Ultimately, the OM642 engine is known for frequent leaks in the lubrication system and the Oil pump It is not considered particularly powerful. Since the engine is sensitive to low oil pressure and no warning signals from the manufacturer are provided in the cockpit, a drop in oil pressure and the associated loss of lubrication goes unnoticed. Only when damage becomes clearly audible or the engine seizes do vehicle owners seek out an auto repair shop. However, by then it is often too late for a smart repair.

Some automotive workshops proceed with the utmost care to avoid particle entry into the main oil channel, and therefore carry out extensive cleaning work before replacing the heat exchanger or turbocharger. Nevertheless, issues continue to occur regularly. Warehouse damages  The damage typically manifests as knocking noises from the crank drive of the OM642 engine and metallic wear, which is usually found in the oil filter but can also be present in the oil pan. Further investigation reveals that the crankshaft is always damaged at least at one main bearing and the corresponding connecting rod bearing. read more