It’s almost 20 years since BMW first sent the 5 Series to market with a four-cylinder diesel engine.

In fact, the 520d version of the E39 5 Series was the only model not to feature the pomp and ceremony of a BMW straight six, and consequently it laboured under the suspicion that it wasn’t really up to the job.

Nic Cackett

Nic Cackett

Road tester
Minor understeer into hairpins is easily checked; coming off the throttle keys you straight into the car’s tolerant back axle

How times have changed. The G30 variant is powered by the same 2.0-litre TwinPower Turbo unit as its predecessor, and it has practically the same peak power as the E39’s 3.0-litre diesel six-pot did in 2003.

Mated to the eight-speed Steptronic automatic gearbox and driving the rear wheels, it equals the acceleration claimed of its larger forbear, too.

That isn’t necessarily extraordinary – a sub-eight-second 0-62mph time is par for the course these days and doesn’t improve on the last generation of 520d – but it helps characterise the level of performance now expected of Europe’s ubiquitous cooking-option engine, no matter the size of the car around it.

Subjectively, the motor lives up to its Swiss Army Knife billing, with its 295lb ft from 1750rpm being sufficient to make the 5 Series feel credibly swift in all circumstances, save perhaps maximum attack.

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The exceptional thing about it isn’t located within the engine bay at all but rather around it. BMW has deployed what it calls Synergy Thermoacoustic Capsule (Syntak) to reduce powertrain noise, and the new technology, combined with other volume-lowering measures such as additional soundproofing in the headliner, does an impressive job of stifling the previously conspicuous rattle of BMW’s industrious common-rail diesel engine.

Combine the muffled serenity with the transmission’s supremely well-oiled and adroit gearshifts and it’ll be a miserly critic indeed who doesn’t accept that the 520d has now moved an additional step closer to the 530d’s exalted standard.

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