It is always a good idea to have a little wooden stick (1ft long) and a paper towel when looking for a used car.
Many of them - regardless of the brand - have problems with the valves getting old. With an engine running smoothly one wouldn't notice the difference between a healthy and a dead sick engine.
Using that stick and the paper will reveal the truth about the engine.
Stick them into the exhaust pipe all the way and gently turn them to wipe off the dirt inside the pipe. The deposit on the paper should be brown to light black with absolutely no oily components.
If the deposit contains oil just forget* about the car, no matter how well it is polished and the seat's condition.
Oil deposits build up in the exhaust system caused for two reasons:
a) the camshaft and/or the valves are worn out to a great deal, so the valves don't close properly when they should, thereby wasting gasoline and oil.
b) the piston rings aren't tight anymore and let oil escape from the sump into the combustion chamber - which won't burn without leaving black "charcoal" deposits in the exhaust pipe.
Both of these signals point strongly towards a major engine overhaul - very expensive!
One further test should be done with every car: a full emergency brake test.
By full brake test I understand braking action with all the muscle power you can apply to the brake pedal. Make sure all persons travelling in that car are strapped properly before performing that test. In times of 4-wheel disc brakes there is no reason why a car should break away to any direction applying full brakes. It must stay stable even at speeds of 260km/h (160mph)(no kidding, the Ferrari Testerosa makes 350km/h
, while my Ford Cosworth just made 280km/h
) within its given track with only minor corrections for uneven ground.
If the car fails the brake test, see * above in text.
Worn out seats are a signal that the car was used regularly and broken in too, like you would break a horse. This is a minor problem which can be solved by an upholstery specialist at fairly low prices.
Unequal wear of the tires (tyres) lead to the conclusion of faulty wheel alignment which can happen for a couple of reasons, like bumping over a sidewalk, kicking a hard obstruction etc. Get that checked thoroughly before purchasing the car.
If the technical and safety sides are covered you might buy the car. The rest will just be cosmetic operations like new polish and new upholstery.
Regards
Hans