Renault Laguna 1.5 dCi

What is it?

The all-new Renault Laguna, here with the smallest engine, a 1.5-litre dCi turbodiesel.

Small engines seem to be coming into their own, even in big cars. As we drive more and more versions of the new Laguna, it becomes ever clearer that the real star of the engine range is the smallest turbodiesel, the 1.5dCi.

The dCi's 109bhp output hardly advertises it as special, but its other qualities - economy, refinement and torque - make it the engine of choice for anyone who can do without the out-and-out grunt of the 3.5-litre V6.

There's nothing rare about this engine. You can find it in Clio and Megane models, too. But Renault has started selling this engine as the true replacement for the old 1.9 turbodiesel (which was heavier, less economical, produced more CO2 and was no more powerful) and expects to sell it as the obvious economy choice.

What's it like?

The 1.5's sheer suitability for the Laguna comes as quite a surprise. True, you have to rev it in a rather un-diesel like way to make real progress, but it is far quieter and smoother than the 2.0dCi 'performance' diesel.

It is also around 40kg lighter, all over the front wheels, which helps steering and even makes the front suspension seem a shade more supple.

This is no performance engine, and it won't pull too well off-boost, but if you allow the fact that it's the cheapest diesel choice, that its 177lb ft of torque at just 2000rpm makes it impressively flexible, that it is naturally smooth and quiet but can rev more sweetly than other diesels, that it emits just 136 gm/km of CO2 and gives the Laguna a touring range of 700 miles-plus, it seems seems a fine choice for a car bought mostly for business.

Should I buy one?

Whether it sells well will depend, we suspect, on whether its owner can bear to tell his peers the engine in his new car is only a 1.5-litre. If he can, the rest will make sense.