CDI are diesel engines with the Common Rail direct injection system, installed on different models of Mercedes-Benz cars. These engines appeared in 1997. They feature 4, 5, 6 or 8 cylinders. They are equipped with chain drive, turbocharger, mostly with intercooler. 2-stage turbocharger is installed on modern versions; AdBlue agent injection system is also met – it serves for reduction of harmful emissions in exhaust gases.
CDI engines consume relatively low amount of fuel, are eco-friendly, offer more power and higher torque. Such renowned manufacturers, as Bosch and Delphi, produce injection systems for such motors.
Popular CDI engines
Index | Quantity and arrangement of cylinders | Quantity of valves | Capacity, l | Output, hp | Torque, Nm | Production years | Mercedes-Benz models |
OM612 | 5, in-line | 20 | 2.7 | 156–170 | 330–400 | 1999–2007 | C-Class W203; CLK-Class C209; E-Class W210; ML-Class W163; G-Class W463; Sprinter W901. |
ОМ651 | 4, in-line | 16 | 1.8 and 2.2 | 109‒204 | 250–500 | 2008 till present | A-Class W176; CLS-Class W218; S-Class W222; SLK-Class R172; GLA-Class X156; M-Class W166; Sprinter W906; V-Class W639; E-Class W212; C-Class W204; C-Class W205; B-Class W246. |
ОМ656 | 6, in-line | 24 | 3.0 | 286–340 | 600‒700 | 2017 till present | CLS-Class C257; S-Class W222; E-Class W213; G-Class W463. |
ОМ642 | V6 | 24 | 3.0 | 184–265 | 400–620 | 2005 till present | C-Class W204; CLS-Class W219; E-Class W211; E-Class W213; CLK-Class C209; CLS-Class W218; E-Class W212; R-Class W251; S-Class W222; GL-Class X164; GLC-Class X253; ML-Class W166; Sprinter W906; V-Class W639; GLK-Class X204; G-Class W463; S-Class W221. |
ОМ629 | V8 | 32 | 4.0 | 306–320 | 700–730 | 2005–2010 | E-Class W211; GL-Class X164; S-Class W221; ML-Class W164. |
OM640 | 4, in-line | 16 | 2.0 | 82–140 | 180–300 | 2004–2012 | A-Class W169; B-Class W245. |
ОМ646 | 4, in-line | 16 | 2.2 | 102–170 | 235–400 | 2002–2010 | C-Class W203; C-Class W204; CLK-Class C209; E-Class W211; Sprinter W906; V-Class W639. |
ОМ647 | 5, in-line | 20 | 2.7 | 177 | 400 | 2002–2005 | E-Class W211. |
ОМ613 | 6, in-line | 24 | 3.2 | 197 | 470 | 1999–2013 | E-Class W210; S-Class W220. |
ОМ628 | V8 | 32 | 4.0 | 250–260 | 560 | 1999–2005 | E-Class W211; G-Class W463; S-Class W220; ML-Class W163. |
OM654 | 4, in-line | 16 | 2.0 | 150–245 | 360‒500 | 2016 till present | C-Class W205; E-Class W213; |
Common malfunctions of CDI engines
Malfunctions | Engines |
Premature wear-out of camshafts, which is determined by the engine construction. | OM612. |
Often burning of electric wires supplying current to fuel injectors and a boost pressure sensor. | OM612, ОМ647. |
Burning-out of fire-resistant washers under injectors, which leads to formation of sludge on them. | OM612, ОМ647, ОМ613. |
Premature breakdown of piezo injectors. | OM651. |
Misalignment of the crankshaft bearings can occur due to oil pump malfunctions. | OM651. |
Intake manifold is apt to crack and loss of air-tightness as it is made of plastics. | OM651. |
Leaks of coolant often occur near the thermostat casing and water pump. | OM651. |
Oil cooler leaks are often due to unreliability of its gasket. | ОМ642. |
Due to cracking of the exhaust manifold and ingress of its wear products into the turbine, the latter breaks down prematurely. | ОМ642. |
The engine is very sensitive to overheating, it results in the appearance of cracks and scoring. | ОМ629, ОМ628. |
Spilling of fuel by injectors, breakdown of the fuel pump. | ОМ629, ОМ628. |
The EGR valve gets soiled relatively soon, as well as intake throttle. | OM640. |
Crankshaft and camshaft position sensors break down often. | ОМ646, ОМ647, ОМ613. |
Appearance of airlocks in the fuel system due to drying out of quick connectors. | ОМ646, ОМ647, ОМ613. |
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