Mercedes M276 Engine - Replacement Cost, Problems & Compatibility

The M276 family covers several raw sub-codes that share the same core 90-degree V6 architecture but differ by displacement, forced induction, and calibration. Identifying your exact sub-code is critical, as components like the turbochargers, intake manifold, ECU, and engine mounts are not universally interchangeable. #### M276.920 - 3.0L V6 Biturbo (245kW / 333hp), 2014-2020 - **Fitted to:** Mercedes E-Class (W213 E400), CLS (C218/C257 CLS400) - **Key technical difference:** Features twin turbochargers mounted in the "hot-vee" between the cylinder banks, paired with direct injection for high torque output. - **Sub-code-specific failure note:** Shares the family timing chain pattern; hot-vee turbo plumbing adds complexity to oil leak diagnostics. - **Interchange note:** Not a straight swap with naturally aspirated variants; the ECU, wiring loom, exhaust manifolds, and cooling systems differ significantly. #### M276.940 - 3.5L V6 Naturally Aspirated (225kW / 306hp), 2011-2015 - **Fitted to:** Mercedes E-Class (W213 E350), Mercedes ML (W164 ML350), Mercedes GL (X166 GL350) - **Key technical difference:** The mid-range 3.5-litre naturally aspirated variant, featuring port injection (or early direct injection in some markets) and a conventional intake layout. - **Sub-code-specific failure note:** Shares the family timing chain and oil leak patterns; carbon buildup is less severe than on later direct-injection-only models. - **Interchange note:** Physically similar to the 3.0L biturbo but requires the correct ECU calibration and specific exhaust routing to run safely. #### M276.950 - 3.0L V6 Naturally Aspirated (185kW / 252hp), 2011-2020 - **Fitted to:** Mercedes E-Class (W213 E300), Mercedes S-Class (W221/W222 S300 Hybrid) - **Key technical difference:** The entry-level 3.0-litre variant, often paired with a mild-hybrid system (e.g., S300 BlueHYBRID) to improve urban fuel economy. - **Sub-code-specific failure note:** Shares the family timing chain pattern; hybrid integration requires specific ECU and electrical compatibility. - **Interchange note:** Cannot be swapped with higher-output 3.5L or biturbo units without extensive ECU, wiring, and hybrid system modifications. #### M276.960 - 3.5L V6 Biturbo (245kW / 333hp), 2014-2020 - **Fitted to:** Mercedes GLE (W166 GLE400), CLS (C218/C257 CLS400) - **Key technical difference:** The high-output 3.5-litre biturbo variant, featuring revised turbochargers and updated engine calibration for increased torque in heavier SUV applications. - **Sub-code-specific failure note:** Shares the family timing chain pattern; higher thermal loads on SUV applications can accelerate oil seal degradation if service intervals are extended. - **Interchange note:** Requires specific engine mounts, exhaust manifolds, and ECU software; not a direct drop-in for W213 sedan applications without significant fabrication.