Mercedes-Benz OM640

2.0 L · inline-4 · turbocharged · diesel · 2004–2012

Also known as: om640, 2.0 cdi a-class, a200 cdi engine, b200 cdi engine

Mercedes-Benz's 2.0 CDI for the W169 A-Class and W245 B-Class — a transverse diesel in a sandwich-floor body, which is the fact that governs every job on it.

These cars carry the engine tilted, low, and above a double floor designed for crash protection, so access bears no resemblance to the longitudinal CDIs of the same period. A procedure written for a C-Class does not describe this installation, and quoted labour that looks disproportionate usually is not.

It carries the CDI family's injector-seal problem. The copper washer fails, combustion gases carry soot up around the injector, and it eventually seizes in the head — the sooty crust is the diagnosis rather than dirt, and treating seals as a service item rather than a repair is what avoids the expensive version.

The turbocharger's vane actuator sticks with soot, producing a limp home under load, and on short-journey cars the particulate filter cannot complete a regeneration — which dilutes the oil with fuel and eventually blocks the filter. These are city cars, so that duty cycle is the normal one rather than the exception.

Cars fitted with this engine

2 generations, across 1 make. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.

Mercedes-Benz

Information, not instruction

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