Signs of trouble

Tyre wear/wheel alignment
Normally, wheel alignment only needs adjusting if steering or suspension components have suffered an impact or been replaced. A good rule-of-thumb is to get a wheel alignment done when you buy new tyres.

When checking your tyre pressures, take a look at the tread, running your hand around in both directions. If your hand moves much more easily in one direction than the other, the tyre is being "feathered" (pictured). Also check whether there's a big difference in wear from the outside edge of the tread to the inside edge. Both are warning signs of wheel alignment/suspension problems.

Another sign of trouble is steering wheel vibrations or "shimmy". You'll need to get the wheels re-balanced. If that doesn't work, get the wheel alignment done by a suspension specialist. Most modern cars have alignment adjustments on all four wheels. You'll almost certainly save the cost of the alignment in reduced fuel and tyre wear.

Radiator hoses
Squeeze the hoses tightly when the engine is cold. Any sign of cracking where you squeeze means the hoses are ready for replacement. Also, when the engine's hot, look for any localised bulging, which indicates a weakened area.

Belts
A broken ancillary-drive belt (they're not called fan belts anymore) can quickly overheat your engine, render the power steering inoperative and stop charging the battery. You don't want that to happen.

Your car might be fitted with the traditional "v" belt, or the modern, flat "multi-groove" belt. You can check it yourself.

Carefully look where the belt wraps around a pulley for any sign of cracking or other deterioration, such as fraying at the edges. Listen for whether the belt makes a squeaking noise when the engine is running. Change the belt if you find any problems.

If you are getting the cam belt changed, replace the ancillary-drive belt too.

Overheating
Cooking an engine (seriously overheating it) is likely to significantly shorten its working life. High temperatures can be caused by coolant leaks, silting up, corrosion and water-pump or head gasket problems. If your engine shows signs of overheating, get it fixed straight away.

Water in oil/oil in water
There are two incompatible fluids in your engine - water and oil. They must be kept apart. Water in the oil, or oil in the water, are sure signs of trouble - often the culprit is a failed head gasket.

Run your finger around under the oil filler cap. Water in the oil will often show up as a gooey "mayonnaise" deposit, which accumulates in the highest point of the engine. Sometimes, repeated short running can also cause this gunk to build up.

Oil in the water will show up as an oily "slick" on the top of the radiator water. Either way, you need to get it checked out promptly.