Our recent first drive in mainland Europe suggested that you won’t find many deficiencies about the way this car operates in top-of-the-line M440i xDrive trim. Albeit for a few different reasons, the same holds true for the 420d.
On the inside, the car is as classy, smart and pleasing to behold as its frontal styling isn’t. Getting the sculptural, lavish-looking fascia used not so long ago to drive up perceived quality levels in the 3 Series, the car mixes technological grandeur with sensory allure so much more effectively than the original 4 Series ever did. I’m still not sure BMW’s digital instruments are as easy to read as they ought to be, but it could be argued that the car’s excellent head-up display more than makes up for that. The driving position is low and snug, in a seat that supports longer-legged drivers brilliantly. The control ergonomics are utterly flawless.
In the back, adult passengers will find somewhat limited room, head room in particular being at a premium; but I suppose that’s why fully half of all last-gen Fours sold in the UK were four-door Gran Coupés (which offer slightly more second-row space). Needless to say, if you’re buying a two-door, you probably won’t make too much use of what’s back here in any case.
When you see BMW coupés of this size out in the wild, they tend to be driven one- or two-up. If my experience is any reliable guide, they’re also often driven daily, and quite routinely a pretty long way – with owners drawn to them for their enveloping habitability and the way they mix driver appeal with first-rate high-speed touring manners so well.
So could this be the first genuine 70-to-the-gallon, long-distance BMW coupé? Well, you’d have to drive it very sensibly; but 55mpg can be conjured without trying at all and an indicated 60 doesn’t take much effort.
BMW’s 48V hybrid set-up adds up to 11bhp and an undisclosed amount of electric-motor torque into the 420d’s crankshaft. The car’s homologated peak power and torque claims remain as they were in old 12V ‘micro-hybridised’ F32-generation 420d; but BMW claims the same 7.1sec 0-62mph sprint for the new version as it did for the old one – and the newbie’s quite a bit bigger and heavier. On-paper lab-certified fuel economy has improved, though, even if you compare this car’s more realistic WLTP combined test result with the old one’s NEDC equivalent – and that’s no mean achievement, considering the subjective gains to the car’s driving experience.
The 420d now has even better drivability, with a more authoritative and torquey sense of low-rev briskness and responsiveness about it than BMW’s already excellent four-cylinder diesels had previously. Much less part-throttle turbo lag is perceptible as you flex your right foot in a higher intermediate gear. The car accelerates notably more keenly and cleanly, and although it still runs out of puff a little once you’re stretched it beyond 3500rpm, it feels plenty fast enough to suit most tastes and purposes. Mechanical refinement is very good, and not just by diesel standards.
Without a doubt, then, this is a powertrain ready to devour long distance very easily indeed. And the chassis, too? Well, you wouldn’t call the 420d’s ride flawless, but it’d be more than good enough to cope very comfortably indeed with faster, smoother motorway surfaces, and it’s allied to handling dynamism that sets the car apart very clearly indeed.