OK, you want a 4x4 vehicle? Are you sure? This is the first question you must ask yourself.

The very nature of a 4x4 vehicle means you are entering the world of lower fuel economy, due to the size of the vehicle, the shape of the vehicle and the fact that while you are using that extra differential, your engine is working harder.

Right, now we have got that out of the way, and you are sure you want a 4x4, your next question is, what do you need it to do? Are your needs mainly leisure, or is this to be a working vehicle? How many passengers do you need to carry? What loads will the vehicle have to transport and also, will you be wanting to tow a trailer or caravan with your new 4x4?

There are many 4x4's just waiting to be purchased within the second hand car market, particularly as with higher fuel costs and higher taxation (in some countries). Many are checking in their larger vehicles for smaller more economic ones and this gives you more choice at good pricing, as a buyer. Please remember one thing though, if and when you decide to sell, you may lose on the deal if the current trends continue.

Lets now look at a few of the things you should be looking out for.

Bodywork first. A lot of older and sometimes more sought after 4x4's have the body sitting on a ladder chassis. I have a preference for these as off road modification seems to be easier. You will need to examine the chassis carefully, looking for areas of rust. Any real problems here should make you walk away unless you are prepared to do some serious welding to put the problem right. However, if the chassis is sound, but the bodywork is tatty, remember that apart from the body mounting points, any rust present does not provide any risk to safety as it is the chassis that provides the strength to the vehicle and not the body mounted on it. If you are looking at a monocoque vehicle, where the strength of the vehicle is within the bodywork, then serious rust in sills etc. should also cause you to walk.

Engine next. Try to arrange for first engine start to be in your presence. A warmed up vehicle pre viewing may be done to hide some problems. On start, have somone look at the exhaust, if any blue smoke (on a petrol engine) comes out in any quantity it means oil has seeped down into the combustion chamber and is being burnt off at first ignition. This could mean either the piston rings are worn or perhaps the valve stem seals are on their way out. Any rectification needed here will cost you a fair bit of cash as it generally means engine out or at least a partial engine strip down. Next, take off the oil filler cap. Examine the inner surfaces of the cap. You are looking for any white material with an appearance of mayonaise. If this is present, it means water is getting into the oilways. This could be a good indication of problems with the head gasket, so again, bear this heavy repair cost against the purchase price. Have a general listen to the engine once running and warmed up, there should be no irregular noises, knocks or other unwarrented sounds. A last point here, is, find out about any belt replacement for this particular vehicle and if there is no proven documentation for the replacement of the cam belt, assume it hasn't been done and factor the cost of this job into the buy price.

Time for the Gearbox. If the vehicle has an auto box, and in my opinion this is by far the best for off roading, check the oil as this is the most important moving part of an automatic gearbox. The best way to check the oil is a two person operation, for safety. Get someone to sit in the cab and have the handbrake on, and their foot hard on the footbrake. With the engine running and the gearbox warmed up and in drive, dip the oil. Make sure you do this from the side of the vehicle and do not stand in front of it. The oil should be exactly on the 'Hot' notch on the dip stick. The oil should be pinkish in colour (some Fords use a green oil) and not brownish. There should be no small particles in the oil and it should not smell burnt. Anything wrong here may suggest the need for a replacement gearbox, again an expense you do not wish for early into vehicle ownership.

Have a general look at the condition of the vehicle as this will tell you what sort of life it has had. Check the interior for wear and tears on the seats, check the mileage, does it agree with documentation? Does the wear on the steeringwheel (shiny means high mileage) and foot rubbers seem to agree with the milage on the clock? If the numbers on the milage do not look completely in line it suggests tampering by the way.

Test drive the vehicle. This is a must. During the test drive use everything on the car. This most importantly includes the four wheel drive system. For most vehicles it's ok to be in 4 high on tarmac, but any difflocking or low ratio options should always be tried on loose ground or you risk breakage and damage.

Remember you are buying a used vehicle so it wont look new, particularly if the vehicle is fairly old. You then have to decide if its worth the buying price and if its worth what you pay to you. Dealers and private sellers are often open to some sort of negotiation and may even give you some sort of warranty too.

The best advice I can give is to take somone with you that knows that type of vehicle.