MOTORISTS are being urged to switch from petrol to diesel cars in a bid to reduce running costs and one major manufacturer is now offering both for the same price.
Chevrolet has started the ball rolling by reducing the cost of its 2.0-litre diesel-powered Captiva by almost £1,500 to make it the same price as the 2.4-litre petrol model.
The diesel model does 39 miles to the gallon in comparison to 32mpg for the petrol version and their respective CO2 figures are 195g/km and 217g/km.
It is now expected that other manufacturers will follow Chevrolet's lead by reducing the price of diesel models to make them the same as their petrol equivalents.
The biggest drawback with diesels is that they cost significantly more than their petrol equivalents, which in the case of the Chevvy was £1,450.
Despite the fuel savings it would take so many years to make-up the difference that most buyers would never achieve it.
Nonetheless, consumer campaigner Which? is urging motorists to switch to oil-burners anyway, pointing out that if they choose wisely they can eventually recoup the initial extra outlay and begin to save money while being greener in the process.
The organisation has produced the Which? Complete Guide to Greener Motoring, which rates the ten best cars for fuel economy.
They are currently the Fiat Panda 1.3 Multijet, Toyota Yaris 1.4 D-4D and Volkswagen Polo BlueMotion, which all average 60.1 mpg.
They are followed by the Mini Clubman 1.6D Cooper at 58.8mpg, the Audi A3 1.9 TDIe, Mazda2 1.4D and Volkswagen Golf BlueMotion at 57.7mpg, the Vauxhall Corsa 1.3 CDTi 90 with economy of 57.6mpg, the Fiat 500 1.3 Multijet at 56.5mpg and the Renault Modus 1.5 dci 86 with economy of 55.3mpg.
These are all diesel models and Which? concludes: "The easiest way to go green and cut down on bills is to switch fuels from petrol to diesel.
"Although diesel cars cost more than petrol cars, they save a packet if they cover lots of miles."
A Peugeot 207 driver could save £247 on fuel over 10,000 miles by switching from a petrol engine to the HDi diesel alternative.
Green car drivers will also save money on tax as the government overhauls road tax in 2009 to encourage motorists to drive cars with lower carbon emissions.
A car that emits less than 100g/km, such as the Polo BlueMotion, will not be liable for road tax.
How they compare
Over 10,000 miles, the driver of a 1.4-litre petrol-engined Peugeot 207 will spend £1,211 on fuel, whereas fuelling the HDi diesel alternative will cost £964, as it averages 62.7mpg rather than 44.8mpg.
This means the diesel driver will save £247, despite the higher cost of diesel fuel. However, this does not take into account the extra £900 the diesel-engined car costs.
Despite owners recouping some of this when they sell the car because of the stronger retained values on the diesel car, the real financial benefits of choosing a diesel model come only if motorists cover higher mileages. Someone averaging 20,000 miles a year would recoup the 207 diesel's extra cost in two years.