No, Mercedes will not use BMW engines: the truth behind the rumor that surprised everyone
They are rivals by nature and although the automotive industry is full of surprises, those with the star have been forced to explain the supposed rumor that Mercedes would use BMW engines.

If true, it would have been one of the biggest surprises that the automotive industry could offer, but the reality is very different and pointed out that sooner or later, one of the parties involved was bound to make a move. And it has been those with the star who have taken the plunge, the ones who had to do it, according to those in the house of one of their eternal rivals.
Just a few days ago, the rumor surfaced that Mercedes was considering acquiring a specific engine from BMW, a four-cylinder engine. Specifically, the gasoline engine, 2.0 liters known internally as B48. The informant source confirmed that it was entirely true that this possibility had been discussed within Mercedes, thus they had been informed from within the luxury brand, but nothing further from the truth.

Mercedes engines will continue to be 100% "Made in Stuttgart"
Markus Schaefer, Chief Technology Officer and member of the Board of Directors of the Mercedes Group, has officially denied, stating that there is nothing true in those statements, and that "The company has no intention of using external engines, much less from a direct competitor like BMW".
Moreover, Schaefer has defended their new range of hybrid engines of four cylinders that will debut in a few months in the new Mercedes CLA, which already complies with the future Euro 7 emissions standard, its modern six cylinders and V8, also confirming that the V12 will continue to be the manufacturer's flagship.
BMW's pride was sky-high and now even more
For its part, BMW has remained silent, it was not the true protagonist of this supposed alliance, but it is proud to have been the supposed choice to supply engines to such an important brand as Mercedes. An unequivocal sign that their engines are a reference.
Thus, you can rest assured that you will not see a Mercedes equipped with an engine from a rival manufacturer; in fact, that policy of installing foreign engines, as happened in the era of Dieter Zetsche with Renault, will not be repeated.