How to maintain your car

The basics

Engine oil
All engine oil has a finite life. Inside a car engine is a tough place to work and so the oil gets dirty from the residue of the combustion process and engine wear. Changing the oil (and oil-filter) at the manufacturer's recommended intervals is essential for getting the maximum life out of the engine. See "DIY oil changes" below for info on changing the oil.

Cooling fluid (anti-freeze, corrosion-inhibitor, or coolant)
Anti-freeze is absolutely essential. It not only stops the engine from freezing on a cold night; it also protects against internal corrosion. But the trouble is that anti-freeze becomes less effective over time.

It's important to get the correct anti-freeze for your car. Some manufacturers market their own in-house brand, which may have a longer life. Check the change interval recommended for your car, and the one recommended on the anti-freeze packaging, and go with the shortest interval. See "DIY coolant changes" below for a guide to changing the coolant.

Brake fluid
Brake fluid absorbs water. If you look at most manufacturers' service schedule, you'll see that the brake fluid should be changed every few years. Few people do this.

Transmission fluid
With a manual transmission it's important to change the fluid at the recommended intervals. But for an automatic transmission it's absolutely essential. Auto transmissions usually have a filter that's changed at the same time as the fluid.

Spark plugs
Some cars are fitted with long-life spark plugs. These are replaced at around 100,000km and require no servicing in between. If you have conventional spark plugs, reset the gaps at around 10,000km and replace them every 40,000km. Find out what type of plugs you need from the manufacturer's service schedule.

Fuel filters
Many cars use a replaceable fuel filter. Engine power will drop if the filter becomes clogged. Change it around every 50,000km, unless the handbook says longer.

Air filters
A clogged-up air filter will cost you in increased fuel consumption and reduced performance. Air filters in most modern cars are accessible and reasonably straightforward to change, perhaps needing only a screwdriver or spanner.

Brake pads/linings
An under-body check should reveal the state of the brakes. Don't rely on your WOF assessments - the WOF brake check just requires that they are working. Waiting until you hear a graunching noise when you brake isn't a good idea. Those graunching noises are metal-to-metal contact, causing damage to the brake discs or drums.

Which is the good oil?

Engines tend to last longer these days, one reason being that modern oils are so much better. But to get the maximum benefit, you must use the correct oil for your engine. You need to know 2 things about oil - its viscosity and its API rating.

Viscosity
This is a measure of the oil's thickness. As it heats up, oil gets thinner or runnier. Modern oils have additives to help stop them getting too thin when hot. The viscosity rating has 2 numbers, one for when the oil's cold, and the other for when it's hot (the bigger the numbers, the thicker the oil). 15W-40 oil behaves like a 15-grade mineral oil when cold and 40-grade oil when hot. Use what the handbook suggests for our climate.

API rating
The American Petroleum Institute (API) sets performance standards for oils. For petrol engines, these start with an "S", as in SJ. Diesel engines start with a "C", as in CH-4. These standards are upgraded every few years. You must use at least the rating that was current when your car was made (check the manufacturer's recommendations). For a car a few years old, using later-rated oil could extend engine life. The latest API rating for petrol engines is SN, but SM, SL and SJ are still current ratings for older engines.

Environment watch
Used oil can be burnt as a furnace fuel. Do the environment a favour and take yours to the collection facilities provided by some service stations and local body recycling depots.

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". 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 4 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 2 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.

Cam belts

This is one item that must not be compromised on. Broken cam belts quite often wreck otherwise perfectly serviceable engines.

Many, but not all, cars use a toothed belt to drive the camshaft(s). This is what you need to do ...

• Find out if your car does have a cam belt. Check the manufacturer's data or ask a qualified mechanic.
• If your car is fitted with a cam belt, find out the manufacturer's recommended belt-change interval. Check with the dealer's service department for your car.
• Get the belt changed at the recommended intervals.
• If you are uncertain about the service history of the car (as with most Japanese imports), get the belt changed.
• If you are buying a car that has a cam belt, factor a belt change into the price you pay, unless you have very good (documented) evidence the belt has been recently replaced. A cam belt change will cost anything from $200 to $700 depending on the car.

Tools that make a difference

Service manual
If you're keen to do some service work, get a service manual. Perhaps the best known of these is the Haynes and Gregory's series. These cost less than official factory manuals and are produced with the amateur mechanic in mind. Find one for your car at auto-parts outlets, specialist or second-hand bookstores, or internet booksellers such as amazon.com.

Ramps
On modern cars, oil filters and the like are usually reached more easily from underneath. That's why garages use hoists so often. At home, a pair of ramps makes the job much easier and safer. Get them from hardware and auto-parts stores.

Oil filter wrenches
You can tighten modern oil filters by hand, but you sure can't remove them that way. There are many different oil filter wrenches on the market. Most operate on the principle of a band that tightens around the filter body. Buy the type that best fits the space available in your engine bay.

Drain pans
Use plastic oil-drain pans to collect oil drained from the vehicle. Pour the used oil from the drain pan into used 2-litre plastic milk containers, label them clearly, and take them to a recycling collection point.

Safety

Fans/rotating parts
A finger caught between a rotating pulley and a belt is likely to be crushed or severed in an instant. Fan blades will do the same - and electric fans can start without warning. When the engine is going, keep your hands out from under the bonnet.

Ignition system shocks
Modern ignition systems can deliver up to 40,000 volts to the spark plug. Don't touch the ignition HT leads (the thick wires that run to the spark plugs) when the engine is running.

Jacks
The jack supplied with your car is designed for changing wheels, not maintenance. If you intend working under the car, use ramps. Alternatively, raise the car with a trolley jack, and support it on axle stands. Never support a car with bricks or concrete blocks, as these can suddenly crumble when subjected to high point-loads.

Used fluids
Brake fluid and used oil can cause skin irritation. Use disposable gloves.

Grooming and quick checks

Fluids
It's a good idea to keep a regular check on the engine oil, coolant and brake-fluid levels (see "The basics" for more info). These are all vital and on a modern car, the engine oil and coolant levels shouldn't change much, if at all. The brake-fluid level will drop very slowly as the brake pads wear. Any sudden change in fluid levels is a warning sign of trouble.

Tyre pressures
Keeping your tyres at the right pressure is important for both safety and fuel economy. Under-inflated tyres wear out more quickly, use more fuel and don't grip as well as tyres set to the correct pressure. We know it's a dirty, boring job, but if you check pressures at least once a month, you'll be safer and save money.

Wiper blades
Wiper blades stay in top condition for only 12 to 18 months. Replace them and you'll really notice the difference next time it rains. You'll usually need to replace only the rubber-blade insert (around $9 to $15 for both blades), not the metal bits.

Vacuuming
Regular vacuuming of the upholstery and carpet will stop dirt getting ingrained and difficult to remove. Small portable vacuum cleaners plug into the cigarette lighter socket, which can be handy if you have to park out of reach of an extension lead. But many people prefer the vacuum machines at service stations - they have lots of suck.

Spray-on/brush-off upholstery cleaners are available in aerosol cans to help keep the seats clean.

Cleaning/waxing
Keeping paintwork free from road grime and bird droppings will help retain the shine. There is a myriad of cleaning and waxing products on the market. For cleaning, choose a car "shampoo". For waxing, we think the polymer sealant-type polishes are easier to use than traditional waxes.

Stone chips
These allow moisture to penetrate under the paint film, causing rust damage much larger than the chip itself. You can buy small pots or pens of touch-up paint. The pens, much like marker pens, are especially convenient. Fill the stone chip with paint using either the paint pen or a sharpened matchstick dipped into the paint. Use several small applications rather than one big blob. You can usually find the manufacturer's paint colour code on an identification plate under the bonnet.

Service intervals

• You can't go wrong if you stick to the manufacturer's service intervals. But you don't need to pay a franchised dealer's hourly rates, unless your vehicle is only a few years old or it's an unusual model. Just find a competent garage and use it for all your servicing. That way the garage will get to know the vehicle, and can warn you of any upcoming work that may be required.

• If your vehicle has a bad case of "postponed maintenance", we recommend a thorough under-bonnet and under-body check. You should be able to get a quote or a fixed price for this work. Some of the servicing chains offer free checks for safety-related items, and fixed costs for some other services - check out the AA Auto Service, Midas or Pitstop chains.

• The AA also offers a range of other technical services to its members and non-members, including mechanical inspections and fault diagnosis. An inspection report will give you a good basis for getting your vehicle up to scratch. Find out from the AA the likely cost of an inspection.