Mercedes OM642 3.0 CDI Engine Specs, Problems, Reliability (2024)

Mercedes OM642 3.0 CDI Engine Specs, Problems, Reliability. The Mercedes-Benz OM642 is a 3.0-liter turbocharged V6 diesel engine that appeared in 2005. The OM642 V6 CDI/BlueTEC engine changed the previous five- and six-cylinder OM647 and OM648 inline engines. This MB 3.0 L diesel unit was used as an engine option for numerous cars and vans produced by Mercedes-Benz as well as under the Dodge, Jeep, Chrysler, and Freightliner brand. The OM642 was produced in DE30LA, DE30LA red, and LSDE30LA versions.

The brand-new V6 CDI has an aluminum cylinder block with a 72-degree V angle which geared up with cast-in grey iron cylinder liners. In 2014, the cylinder liners were replaced by the Mercedes-Benz’s “Nanoslide” cylinder wall coating. Engine’s aluminum crankcase weights just 41 kg. The OM642 has a forged steel crankshaft which rotates in 4 bearings, forged steel lightweight linking rods, and aluminum pistons with recesses in the piston crowns for the ideal combustion procedure. The crankpins are offset by 48 degrees.

The engine also has a stabilizing shaft which counter-rotates at the very same speed as the crankshaft. On top of each cylinder bank, there is an aluminum cylinder head with 4 valves per cylinder (24 valves total) and consumption and exhaust overhead camshafts (DOHC). Valves are actuated by camshafts through roller-type web cam fans with hydraulic valve clearance settlement. The camshafts are chain-driven. The engine uses a double-bush (duplex) timing chain. This chain also drives the balancer shaft and the high-pressure fuel pump. Head covers are aluminum as well.

Mercedes OM642 3.0 CDI Engine Specs, Problems, Reliability

The OM642 3.0 L engine has the third generation of the common-rail direct injection system. It features piezo-ceramics injectors instead of the formerly utilized injectors with solenoid valves. Injector nozzles have 8 holes (previous engines had seven). The brand-new piezo-injectors allow making up to 5 fuel injections per cycle. The high-pressure pump provides an optimum injection pressure of 1,600 bar (23,000 psi).

This diesel motor is turbocharged by a Variable Nozzle Turbine turbocharger (VNT or VGT – a variable geometry turbocharger) – Garrett GT2056VK. VNT turbocharger is electronically controlled by ECU (Bosch EDC17) and able to differ the angle of its turbine blades to match the operating status and loads offering the ideal increase pressure. The consumption system is geared up with a downstream intercooler which minimizes consumption temperature level by approximately 95 degrees Celsius.

To satisfy more and more stringent emission guidelines, there are 2 oxidizing catalytic converters cleaning up the exhaust gases of the brand-new Mercedes 3.0 L V6 diesel engine. In addition, the engine has actually a cooled exhaust gas recirculation system (EGR/AGR) and utilizes a diesel particulate filter (DPF) to lower exhaust emissions even further. Some latest cars may have BlueTec AdBlue urea injection for NOx decrease.

In 2017, the producer launched its newest diesel motor – the Mercedes-Benz OM656. This inline six-cylinder engine will change the OM642 V6 in the near future.

Mercedes OM642 Engine Problems and Reliability

In general, the OM642 engine has actually proven to be quite trustworthy. Near a mileage of 100-150k miles, auxiliary engine systems begin to fail.

The first thing that begins to stop working on this engine is the crankcase ventilation system. Driving mostly in the city and low-quality fuel add to the development of a large amount of deposits inside the consumption system. The crankcase ventilation system vents to the consumption of the turbocharger. The vented oily air quickly goes through the turbo blades and this oil and sludge start to collect on walls of the consumption channels, swirl valves and etc. Mercedes-Benz has specified that this engine feature is “typical”.

For vehicles equipped with an OM642 3.0 L diesel engines, it will be valuable to clean an air consumption manifold, intake pipes, and crankcase ventilation pipes every 60-80k miles. Otherwise, the swirl valves might be stuck and a straining electric drive motor will blow a fuse that manages other sensing units. If it will occur, the vehicle goes into the “limp home” mode and limits engine speed to 3,000 rpm due to disabling of the important engine systems.

The next issue applies to engines manufactured prior to 2010. The pre-2010 OM642 engines frequently had oil leakages from the oil cooler. This issue occurred due to heat-related seal degradation. In 2010, the producer replaced the previous orange seals with more long lasting Viton seals. New seals have a purple color.

Injector copper seals are understood to stop working, causing a buildup of heavy carbon deposits around the injector. The car begins to lose and smoke power. As a result, all of it ends with the failure of the fuel injectors (known as “Black Death”). Some individuals advise utilizing the Honda Accord 2.2 Diesel injector seals in applications for Mercedes CDI diesels instead of specified MB sealing washers. Another factor for the black smoke from the exhaust pipe in some cases related to a breakdown in the radiance plug controller.

The manufacturer likewise changed the TWC temperature sensing unit (part no. A005 153 40 28) with a brand-new sensor that defined part no. is A007 153 74 28. The previous sensing unit was vulnerable to fast failure (diagnostic code is P2031).

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Mercedes OM642 3.0 CDI Engine Specs