Car Choice: Can LPG blend a desire for luxury with the need to watch your pennies?

John Marsh has always dreamt of owning a Jaguar and reckons he has reached that stage in life where luxury is important. Now, with the collapse in second-hand car prices and a budget of £8,000, he can afford one. His concern is being able to run it, and with petrol getting more expensive he wonders whether conversion to Liquid Petroleum Gas (LPG) is a good idea. John says that the car will mostly be used around town.

At roughly half the cost of petrol, LPG makes all sorts of sense. Indeed, a friend of mine has just converted a Saab to run on the gas and reckons that although the fuel consumption is slightly worse, he is still getting the equivalent of 60mpg when taking the price into account. The catch is that my friend is a mechanic. He scrounged all the plumbing and knew what he was doing, so the conversion cost him just a few hours of time. The rest of us would have to budget at least £2,000 to convert a Jaguar. It is also important to find a garage or engineer who can carry out the conversion properly. Many specialists I have spoken to say that the kits and time allowed to carry out the conversion are not enough. It can take up to a week to install properly and not everyone is prepared to pay for it. So, if a garage says they can do it for £500, beware. A good starting point is the LP Gas Association, who can point you towards an authorised installer. Ideally, though, John ought to consider finding a vehicle that has already been converted.

A car for the head

If John is only going to do a modest mileage around town, should he really worry too much about the miles per gallon, which in a luxury petrol car is always going to be poor on short start-stop journeys? Perhaps a cheap though comfy car for just a few thousand pounds would be ideal. That's easy because John could buy a Lexus, BMW or Mercedes. These cars, though, would not be fulfilling his requirements for a classic car. OK, so let's go with a Jaguar S-Type then. And, with just £2,000 to spend, John could buy himself exactly the car he wants. It would be a 1999 3.0 V6 with between 115,000-130,000 miles on the clock. I managed to find several with full service history and all the extras that John expects, such as climate control and leather. As we regularly point out, the biggest-single motoring cost is not fuel, but depreciation. So I reckon that John ought to go for this cheap option as even short term he won't lose any money – or no more than £1,000 anyway – and he only has to worry about pumping fuel in every few weeks. If he loves the car then maybe treat it to an LPG conversion in the future.

A car for the heart

An LPG Jaguar? Well, I could only find three of those when I looked. One was a 2002 XJ8 3.2 V8 Executive for £5,995 at a car dealer. It was green, upholstered in cashmere leather and returned a claimed 40mpg, rather than half that if it relied on petrol alone. John needs to know that all LPG cars start with petrol and then switch over to gas, so he will never be entirely free of stopping at the pricey pump. For the same price, John might also want to consider a 2001 X-Type 3.0 V6. It has covered a little more than 100,000 miles and has leather, sat-nav and cruise control. That sounds good, but I haven't heard particularly good things about this model, which seems to have a patchy reliability and is not especially nice to drive. Finally, for just £1,950 a 1994 Jaguar XJ 3.2 Sport with the usual dose of leather, air conditioning and alloy wheels. It is the old square-shaped model, which isn't to everyone's taste but is still a Jag'. Not only that, there are bills to show for a lot of recent work, so this might suit John perfectly.

Please write to Car Choice, Features, IndependentHouse, 191 Marsh Wall, London E14 9RS, or email James Ruppert at carchoice@independent.co.uk, giving your age, address, phone number and details of the type of vehicle in which you are interested and your budget.