Mercedes Turbo

Mercedes turbos from the OM611 era to the M276 V6 biturbo: the engine code as your starting point

Across such a broad Mercedes range — Classe A, B, C, E, CLA, GLA, GLC, CLS, ML, Sprinter, Vito, Viano, Citan — the engine code stamped on the block remains the only reliable way to identify the exact turbo. The same model can house two entirely different engine families depending on the year of manufacture or power output, and the corresponding turbos are not interchangeable. Before anything else, check that code.

Diesel: the OM646 family dominates, but its variants multiply the references

The majority of diesel turbos in the catalogue cover the OM646 blocks and their variants: OM 646.951, OM 646.961, OM 646.962, OM 646.963, OM 646.966, OM 646.980, OM 646.981, OM 646.982, OM 646.986. These codes cover the 200 CDI and 220 CDI across several power outputs (102, 116, 122, 136, 150, 170 hp) and appear on models as varied as the Classe C, Classe E, Sprinter and Vito. A 220 CDI 150 hp Classe C (OM 646.963 or OM 646.966) does not take the same turbo as a Sprinter 111 CDI fitted with an OM 646.990: identical power output is not enough — the engine code is decisive. The OM611 blocks (older generation, notably the Sprinter 211/311/411 CDI) and OM651 (Sprinter CDI 2.1 bi-turbo, more recent) are also represented, but their turbos are distinct and not interchangeable with those of the OM646. On the 6-cylinder diesel side, the OM642 blocks (OM 642.850, 852, 854, 858, 920, 921, 950…) are fitted to the 280 CDI, 320 CDI, 350 CDI and BlueTEC on the Classe E, C, CLS, ML and GLC; the OM612 covers the 270 CDI on the CLK, CLC and earlier-generation Classe E. For compact light commercials (Citan, entry-level Classe A/B), the K9K, OM607 and OM640 codes introduce yet further turbo families, often fixed-geometry and smaller in size.

Petrol: M270, M271, M276, M278 — four families, four different turbos

Turbocharged petrol blocks span four clearly distinct families. The M270 (M 270.910, M270920, M270921) is fitted to the Classe A/B/CLA/GLA 160 to 250 in their petrol versions; the M274 shares certain applications with the M270 on the Classe C. The M271 (M271.820, M271.860, M271.861) covers the 200 CGI and 250 CGI of an earlier generation. The M276 (M276.820, M276.823, M276 DE30 AL) is a V6 biturbo found on the E 400, C 43 AMG and GLC 43 AMG — two separate variable-geometry turbos per engine. Finally, the M278 (M278.922, M278.932) is the V8 biturbo of the S 500 and E 500, again with two turbos per block. Gradual power loss, a whistling noise under acceleration or blue smoke when the engine is warm are the most common symptoms before complete failure; on V6 and V8 units, oil hose leaks on the turbo accelerate bearing wear. Always address the root cause (oil quality, EGR fouling, air leaks) before any replacement. The turbos on offer are available new or reconditioned depending on the manufacturer's reference.