Alan,Some makes of car offer a diesel or petrol engine at the same price (then the calculation is a matter of what the difference in MPG is) - although most makes do charge more. Diesels also tend to have more pulling power (torque), giving good mid range acceleration (so a 1.6 diesel can be a better choice than 1.6 petrol for overtaking) and making them more suitable for towing and for use in 4x4s (where the lower MPG can make a big difference). Diesel fuel has higher energy density than petrol and the engines are more efficient (which gives the improved MPG), although they are typically heavier than petrol engines - which is why the MPG difference is less notable with smaller, lighter cars.You can also use recycled cooking oil and other bio fuels with a diesel (which was originally designed to run on peanut oil), reducing CO2 emissions further (they already tend to be lower than petrol engines).In general diesel engines are also more reliable than petrol (they don't need electronic ignition systems and are built to withstand greater stresses, which is why they are heavier).The latest diesels (such as the Honda 2.2 and the new Subaru Boxer engine) are pretty refined and nowhere near as clattery as older diesels (especially when they've warmed up).We're soon to buy a new car, and although we don't do the sort of milage that warrants a diesel engine, some of the cars we're considering seem to be better suited to particular diesel choices than their petrol options.
David Fox ● 6779d