Mercedes-Benz is reportedly in advanced discussions to source BMW’s four-cylinder petrol engines for a wide range of its future models. The move, first reported by Germany’s Manager Magazin, could see one of BMW’s most important powerplants, the B48, playing a central role in both brands’ internal combustion futures – and by extension, BMW’s.
According to Manager Magazin, the two German rivals are at a high level of planning and negotiations, with an announcement expected before the end of the year. If finalized, the deal would represent a major shift for Mercedes, which has recently slowed its EV roll-out in response to weaker-than-expected demand and is rethinking its ICE strategy.
Why Mercedes Wants BMW’s B48
For Mercedes, the attraction is clear. The B48 engine family already meets Euro 7 standards and has been engineered for both longitudinal and transverse layouts. That flexibility means it can be dropped into everything from compact cars like the CLA and GLA to mid-size staples like the C-Class, E-Class, and GLC – not to mention the upcoming “Little G.”
By contrast, Mercedes’ new in-house M252 four-cylinder, developed in Germany and built in China by Horse (a Geely-Renault joint venture), is limited in scope. Offered in the latest CLA with outputs ranging from 136 to 190 hp, it works well in mild-hybrid form but isn’t engineered for plug-in hybrid or range-extender applications. The B48, however, is already proven in such roles, giving Mercedes a ready-made solution without massive new R&D investment.
What This Means for BMW and MINI
For BMW, supplying engines to Mercedes would mark a historic first: two German luxury carmakers sharing combustion engines. It’s being framed as a “strategic step to cut development costs,” but it also signals that BMW has no intention of walking away from refining the B48 any time soon.
The B48 powers every combustion MINI model today, from Cooper S to X2, and if BMW is about to commit to a deeper, long-term development cycle for the engine, it suggests both brands will continue to benefit from upgrades in efficiency, emissions compliance, and potentially performance.
A Shared Future and Shared Costs
The partnership could go even further. Reports suggest the two companies may look at shared production hubs, including the possibility of a U.S.-based engine plant to avoid mounting import tariffs. There’s even speculation that gearboxes could be part of the agreement in the longer term.
If this deal is signed, it won’t just reshape Mercedes’ ICE lineup. It could also lock in the B48 as BMW’s (and MINI’s) mainstay four-cylinder for years to come – a reassuring sign for those of us who still believe in the future of a turbocharged MINI Cooper S or X1 with petrol power.