In Woody Allen’s 1973 sci-fi send-up Sleeper, his character finds a 200-year-old Volkswagen Beetle in a cave and starts the engine, which turns over without the slightest hesitation. Allen could have substituted a W115 Mercedes 200D in the same ridiculous but truth-based scene. Mercedes diesels, like air-cooled VW flat-fours, are pretty much indestructible. Now, Mercedes has released a new-generation of its venerable four-cylinder diesel.
The latest OM 654 2.0-liter turbo-diesel four-cylinder debuts in the Euro-spec 2017 E220d this spring, and sometime later in the U.S. (with a higher numeral, due to our hubris over engine size). It replaces the OM 651 2.1-liter diesel in service worldwide since 2008, although our time with it was considerably shorter; it arrived here in 2013, first in the GLK250, and then in the E250 and ML250 BlueTec models. Of that engine’s three strengths offered in Europe (250, 220, and 200), we received only the most powerful. The new engine?in 220 strength at least?makes 195 horsepower at 3800 rpm (up 25 hp) and 295 lb-ft of torque between 1600 and 2400 rpm. Compared to our current 2.1-liter engine, it achieves the same horsepower but nowhere near the 369 lb-ft that made our 2014 E250 sedan sneaky fast. Mercedes hasn’t confirmed U.S. specifications yet, but we’ll bet our version will produce more torque.

More so than output, the big news is the OM 654’s cast aluminum block, as Mercedes is waving goodbye to the trusty c...