The only uncharacteristic traits about the diesel model are the noise and vibration levels, which appear significantly higher than in any petrol-powered BMW car. That has largely to do with the turbodiesel engine's high compression ratio of 16, compared with only 11 for the 525i.

Of course BMW could have done more to insulate the car better. Idling, the diesel clatter is most pronounced, especially to passers-by. You might even say it is worse than a Hyundai taxi.

This being a new car, it is not unreasonable to assume that things could worsen later.

But when the car is cruising, the engine noise becomes imperceptible and the vibration far less noticeable. In fact, when the 520d is in motion, you forget that the car is merely a 2-litre machine.

Its power delivery is prompt and linear, and gear changes by its six-speed autobox are smoother than some of the dual-clutch jobs out there.

And everything else is Beemer-ish, from handling to brake response to cabin ergonomics.

christan@sph.com.sg

This concludes a two-part assessment of the BMW 520d. Watch out for similar long-term tests of other diesel models, powered by Caltex Techron D.

This article was first published in The Straits Times.

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