THE 10 BEST AND WORST ENGINES MADE BY MAJOR AUTOMAKERS

Worst Mercedes Engine: M139

Let’s be real—sometimes even Mercedes gets a little too clever for its own good. That’s kind of what happened with the M139 engine in the 2022 AMG C63.

This was supposed to be a new era: smaller, more efficient, and hybrid-assisted. But instead of a big, throaty V8, what we got was a tiny turbocharged four-cylinder with some battery help. Yes, it makes 671 horsepower on paper, but something about it just feels... off.

For fans who loved the rumble and punch of the old V8s, this new setup felt like a downgrade—no matter what the performance numbers say. Plus, all the added complexity (turbo, battery, electric motors) makes us wonder how it’ll hold up in the long run. It might be fast, but it’s missing the soul that made AMG special. The good news? Mercedes has already announced the V8 is coming back in 2026. Smart move.