Reports indicate Mercedes-Benz is in advanced negotiations with BMW to source the latter’s four-cylinder petrol engines for future models. The move is described as part of Mercedes’s response to slower-than-expected electric vehicle uptake. The discussions have progressed significantly, with a potential announcement expected before the end of 2025. If finalised, this would be the first time Mercedes and BMW share core combustion powertrain technology.
Engines & Technical Basis
The engine under discussion is BMW’s B48 2.0-litre turbocharged inline-four, currently deployed across BMW and MINI line-ups. It is Euro 7-ready and adaptable for longitudinal and transverse applications, making it suitable for multiple Mercedes platforms. Output configurations in existing BMW use range between 154 BHP and 302 BHP, depending on tune and hybridisation. Production of the B48 is centred at BMW’s Steyr, Austria, facility, with the possibility of US manufacturing under review to offset tariff exposure.
Mercedes’ Current Limitations
Mercedes’s current small-capacity unit, the M252 1.5-litre four-cylinder turbo-petrol, is produced in China. It is offered in the CLA in outputs of 136 BHP, 163 BHP and 190 BHP, paired with an eight-speed dual-clutch transmission and a 27 BHP integrated starter-generator. However, the M252 is restricted to mild-hybrid functions and cannot support full plug-in hybrid or range-extender roles, limiting Mercedes’s ability to scale electrified petrol offerings within Euro 7 compliance.
Potential Applications
If adopted, the B48 could feature in upcoming generations of the CLA, GLA, GLB, C-Class, E-Class and GLC, alongside the planned compact SUV known internally as the “Little G.” The flexibility of the engine also makes it viable for plug-in hybrid integration across Mercedes’s global portfolio. Discussions reportedly also extend to gearbox sharing.
Industry & Market Implications
This development underscores a pivot within Mercedes, where combustion technologies remain a parallel focus despite earlier plans for an all-electric transition. BMW benefits from volume expansion for its B48 production, while Mercedes gains access to an immediately compliant unit without significant additional R&D. The wider implication is a recognition by both brands that electric adoption is lagging behind initial projections, necessitating new long-term ICE strategies in Europe, North America & Asia.
Conclusion
The outcome of these negotiations will depend on regulatory clarity around Euro 7 timelines, customer demand for plug-in hybrids versus BEVs, and production cost structures. Further announcements later in 2025 will determine whether this cooperation remains limited to engines or expands into wider component sharing.
