Perhaps the least-appealing aspect of a diesel-engined car is the motor's noise.
That clack-a-clack, clack-a-clack at idle; the cacophony when the engine is at high revs and working hard.
Memorably we used a Holden Vectra diesel for a 1500km round trip some years ago. It returned outstanding fuel economy and, provided you kept up momentum in going where the modestly-powered diesel struggled, good open road pace.
But the noise of the Isuzu engine became a bit wearing and detracted from what otherwise was an enjoyable driving experience.
But modern diesels need not be old rattlers or unrefined, as the sweet units in Peugeot's 406 HDi proves.
It's a smooth, refined and quiet engine that also delivers a hefty punch, producing performance that complements the 406's highly competent chassis.
The motor is a 1997cc, two-valve-per-cylinder with direct injection, a turbocharger and an intercooler.
It makes 80kW of power at 4000rpm and a strong 250Nm of peak torque at 1750rpm.
On road that translates to 0-100km/h acceleration in 13.5 seconds in the station wagon as tested. The sedan, which is 15kg lighter, cuts out the sprint in one second less.
Those aren't startling figures, but that's just what they are, figures printed on a page.
In the real world, the acceleration feels strong and the power progressive. There's little turbo lag and the 406 has no difficulty keeping pace with city traffic.
Peugeot says the 406 HDi wagon has a 185km/h top speed (the sedan will do 191km/h).
As with all diesels, the HDi's long suit is fuel economy, and Peugeot quotes urban cycle fuel consumption of 9.3 litres per 100 kilometres for the HDi automatic.
On the highway cycle it will do 5.1 litres/100km.
So you'll cram plenty of kilometres into each 70-litre tank of diesel.
The four-speed adaptive automatic gearbox is a mixed bag.
Its upshifts are smooth enough, but we find the gearbox unnecessarily fussy. There's some hunting around as you change your foot pressure on the throttle at cruising speeds, and the automatic downshifts as you slow down and stop at traffic lights or compulsory stops can be jerky.
That sort of behaviour is also common to the auto gearboxes in the 206 Coupe Cabriolet and the 607 where it becomes tiresome. But the torquey diesel motor seems better suited to the gearbox than the petrol motors. Certainly the 406 HDi is the best application of the Peugeot auto gearbox that we've encountered.
We'd still prefer a manual, though. The diesel's torque will keep gear-changing to a minimum in a manual, and you'll also get minor fuel economy and performance improvements.
The 406 is now a relatively old car, but its chassis is still a standard-setter.
The steering - engine speed-related power-assisted rack and pinion - offers plenty of feel and is wonderfully direct.
The car turns-in very quickly and crisply. In fact, initially you find yourself turning the wheel too much, the car responds in a split-second and you're into the corner more sharply than you want to be. A small amount of passive rear-wheel steering is built into the rear suspension geometry, helping the turn-in to corners.
A few minutes at the wheel and a few corners down the road and you've made the necessary adjustment for the steering's directness.
Once you're accustomed to the car's rapid response to steering inputs you can start exploiting the handling with confidence.
There's a little bit more body roll than you might normally associate with a car with such finely-tuned steering, but though the 406 moves around a little on its wheels it offers a very good driving experience.
The roadholding is excellent and the 195/65 R15H tyres provide excellent grip.
A winding road is a real joy in a 406 and the car gives the impression it's having as much fun as you are.
It flows from corner to corner in a seamless manner, the chassis possessing superb balance and poise.
Ride quality is outstanding, the MacPherson strut front/multi-link rear suspension providing a beautifully supple ride. Bumps of all sizes are coped with and virtually no road shock is felt by the occupants. The mix of suspension and seat springing ensures occupants get true ride comfort.
Brakes are strong, though when you first drive the car they can feel a little sudden. You soon adjust.
Headlight and windscreen wiper performance is good.
In fact, it's not only the 406 HDi's gearbox that does some thinking for you. It also turns its headlights on and off depending on the amount of light its sensors detect, and the windscreen wipers will come on when it's raining.
Initially this autonomous action irritated me but after a few days I was comfortable with it. I'm all for automation, but let's hope it doesn't go too far.
The cloth upholstered seats are well-shaped and there's good legroom and headroom in front and rear cabins. The loadspace is generous and the 406's interior is well-shaped for load-carrying.
Standard equipment includes 15-inch diameter alloy wheels, ABS anti-skid braking and electronic brake force distribution. Electronic stability control and cruise control are added-cost options.
Driver and front seat passenger get front and side airbags, and the rear seat has three lap/sash seatbelts.
There's remote-control central door-locking and power windows and exterior mirrors. The mirrors are also heated.
Front and rear fog lights are standard, as are 60/40 split-folding rear seatbacks. The climate-control air-conditioning has a pollen filter.
The Compact Disc player provides good sound; a six-disc loadspace-mounted stacker can be fitted at added cost.
A trip computer is also standard.
The 406 HDi wagon is a stylish, well-designed and finished car which offers excellent accommodation for five passengers and the ability to carry large loads with the rear seatbacks folded down.
On the open road it provides good performance and will lope cross-country at good pace. The excellent steering, agile chassis and excellent roadholding make it a superb point-to-point car.
The diesel motor ensures good fuel economy and is a surprisingly quiet and refined unit.
Our only reservation is the automatic gearbox. If we were buying a 406 we'd opt for a manual.
AutoPoint road test team: story and photographs by Mike Stock.