| First Drive | Barcelona, Spain | SEAT Leon 2.0 TDI 140 CR |

The first lot of Pumpe Duse (PD) diesel engines were a revelation a decade ago in the VW Golf Mk IV. Sadly their rich timbre - akin to a smoothie maker pulping walnut shells - became more difficult to deal with as the years wore on, especially with the introduction of quieter common rail diesels across VW Group cars. Hard to believe, then, that one of SEAT's most popular cars, the 138bhp diesel Leon, was still rocking a PD under the bonnet. Until now.

In the Metal

You won't notice any visual changes - this is a simple engine swap. We must say, though, that the Leon is becoming noticeably more reliant on bright colours, flashy wheels and glossy interior trim to look fresh. Maybe familiarity breeds contempt, but the Leon isn't as striking as it once was.

What you get for your Money

To start with the 138bp TDI common rail engine is only available with SE and Sport specifications. SE versions get 16-inch alloys, climate control, cruise control, a USB socket, leather multi-function steering wheel and a ream of traction and braking aids, abbreviated thus: ABS, TCS, XDS, ESP and EBA. All that for £18,570, a £440 increase over the PD car.

Sport endows your wheels with an additional inch, it jazzes up the interior trim and changes the suspension settings. A six-speed manual gearbox is standard and a six-speed DSG automatic optional. Deliveries begin January 2011, order book open now.

Driving it

If you were expecting a revelation, prepare to have your expectations curbed. Yes, the common rail engine is tangibly smoother through the revs, and quieter both at idle and the limiter, but this doesn't feel like a quantum leap. Maybe that's the result of SEAT getting quite good at dampening the PD's combustion clatter later on in its lifecycle.

In gaining this extra smoothness, a fraction of the punchy delivery of the PD is lost. There's slightly less urgency than there was, even though torque hits the same peak (236lb.ft) at the same point in the rev range (1,750rpm).

Let's not complain too much, though, because this is still the more satisfying engine available. Its torque spread feels more even so holding onto a gear serves more purpose. Power is the same (138bhp), though the 0-62mph dash goes by 0.2 seconds slower than before, at 9.5 seconds.

But here's the killer hook: economy goes from 50.4- to 58.9mpg combined, and CO₂ from 147- to 125g/km with the six-speed manual gearbox. It drops two VED bands, meaning zero in first-year VED and £90 thereafter instead of £125. A six-speed DSG gearbox is still available.

Worth Noting

The death of the 138bhp PD engine in the Leon means SEAT's diesel range is now entirely common rail. We found it a little odd that the company would wait so long to modernise the model we assumed would be the best seller. As it turns out it's not - the FR 170 TDI is, which went common rail a while ago. See, what do we know?

Summary

SEAT's replacement of a PD engine with a common rail one is a transformation that few buyers will really notice, but it's typical of a company that's making constant refinements to its cars for the benefit of the customer. The result here is a quieter, smoother and more economical engine. Job done.