Small Faults, Big Repair Costs

Most owners can sense when their car is not running well or using too much fuel. When it doesn't come back any better after a service, they often sell it.

Seemingly minor faults that can escape a pre-purchase inspection or service can leave the next owner with a big repair bill.

There was a time when you could see what was not working in a car and fix it. Because cars since 1986 have become so heavily dependent on computers and other electronics, they suffer from the same failures as home computers and there is nothing to show you what needs fixing.

Just as you would be struggling to find anyone still using a computer purchased in 1986, cars as recently as 1997 are locked into old generation electronics that have a use by date and stop working.

Unlike a computer, it is not always an option to throw away the whole car just because an electronics function has failed. Yet in many cases, the electronics part is no longer available. It can be hard to find anyone who can be bothered fixing old generation electronics when they usually don't follow the same principles or use the same parts as today's computers.

Over 15 years ago, I was predicting that a failed automatic transmission would cause a car to be scrapped prematurely never believing that a failed minor electronic part could do the same. It is now happening.

There are also other manufacturing short cuts that have made simple routine repairs extremely difficult or time-consuming.

What does this mean for used car buyers?

Never dismiss even a minor fault as insignificant when the part that is causing the problem or what it is attached to might be worth thousands or can't be sourced any more. Before agreeing to buy any used car with what seems like a minor fault, check out what it will cost to fix and if in fact, it can be fixed.

TROUBLE SPOTS

Temperature Gauge reading too low or not moving after start-up
This can be a nasty fault when most owners don't report it. There is a mindset that sees a cold running engine as a bonus because it is not overheating but the disaster waiting to happen is severe.

It is rarely picked-up in a short test drive or inspection. Either way, it is warning you of a fault that can cost serious dollars to rectify on many of today's cars.

Recently, I inspected a small European hatch that had just been through a $1500 dealer service that included a new water pump and cam belt. Because no one picked the low reading temperature gauge, most of the repair will need to be stripped down and done again at the owner's cost.

A low reading temperature gauge means one of two things -- the gauge is faulty or the engine is in fact running too cold. Most good service centres have a special gun which you can point at various sections of the cooling system and it will give you a temperature reading of what's happening inside. This will eliminate or confirm whether the gauge is at fault.

If it is at fault, tracing a wiring or instrument panel fault or sensor failure is relatively straightforward but labour-intensive if the dash has to be dismantled.

If the gauge is working properly, then it almost certainly is warning you of a thermostat that is stuck wide open. This will prevent the engine from ever warming-up during most trips forcing the computer to run a cold start mixture rich in fuel and pollution all the time. Apart from the extra cost, this extra fuel washes away the oil inside the engine robbing it of vital lubrication. As the oil becomes saturated with unburnt fuel, it will kill the oil generating excessive engine wear. It will also prevent the heater and demister from working properly.

Thermostats that are stuck open can also suddenly stick shut and cause the engine to overheat and seize up without warning. Replacing a thermostat was once a simple and cheap engine repair. It can now be one of the most difficult when it is often placed behind the cam belt and water pump and force the removal of the front of the engine just to access it. European cars can be the worst and smart service centres are replacing thermostats every cam belt change or five years as a precaution when that part of the engine is already stripped down.

The latest trend to eliminate temperature gauges in European cars means there is no early warning of a failed thermostat unless it causes overheating. When continual cold running generates such huge emissions and fuel consumption problems, there is a strong argument for a temperature gauge being a compulsory component of any emissions requirements.

Temperature gauges should rise to normal operating temperature within minutes of start-up. If they don't, find out why

Engine stalls with the air-conditioning on
This is a mechanic's worst nightmare. In the old days, a simple solenoid pulled harder on the accelerator to give the engine more power to run the compressor. Now, it's all controlled by computers.

If you have ever watched a computer geek program your home computer, you soon realize there is a million ways to deliver the same end result. The way car computers are programmed seems to depend on what the factory technician had for breakfast that day. Again, the European cars are the worst.

If there is an extra function needed for a special market requirement, the geek is under pressure to find a spare electronic pathway in the existing electronics to carry out that function. This can render any self-diagnostic function useless when the function may draw on a combination of electronic modules and computers.

I watched several specialists work on a small German hatch recently as they tried to trace and isolate all the hidden modules that could have been responsible for boosting engine power as the air-cond is switched on. After their special diagnostics equipment had isolated a fault in the designated unit hidden under the battery, its $800 replacement made no difference. With new electronics parts, that part is yours whether it fixes the problem or not. It is now suspected that the relationship between this part and the main engine management computer is at fault. By the time this relatively simple fault is fixed, it will cost somebody well over $2000.

I had a similar problem with a prestige Japanese car. Its instrument lights, courtesy light and intermittent wipers just stopped working. After conventional diagnostics failed to find any faults, I discovered that these functions had been routed through an expensive and obscure body computer that you couldn't buy any more.

The original wiper blades and the pantograph sections that support them are one of the most carefully engineered parts in a car when they have to stay stuck to the screen at speed, follow the contours of the glass and not damage the windscreen. Too many dealers and service centres are throwing these expensive parts in the bin and substituting them with nasty throwaway plastic-backed wiper blades that don't fit or fall apart leaving a large exposed retaining clip to carve a groove in the windscreen.

I have received so many calls from clients and friends stranded on wet weekends with detached wiper blades and deeply grooved windscreens after these nasty substitute items have failed, that I keep a stock of factory blades and clips to keep them mobile. Two in particular where money was no object had taken their cars to factory dealers to ensure factory parts. They were distraught after I had pointed out the plier gouges on the wiper frames which had been butchered to hold these shonky wiper blades in place. I was able to persuade both dealers to replace the whole wiper blade assemblies with the factory originals when the owners were not consulted.

If dealers or service centres have an issue with the cost of factory wiper blades then it needs to be dealt with. In the meantime, the owner must be given the choice and warned if they are going to be heavily compromised in such a vital safety area. There are also good quality aftermarket wiper blades if price is still an issue but a windscreen replacement which several friends are now facing can quickly make the genuine item look cheap.

Check the wipers front and rear. If they have plastic backed blades with ends that look like they have been roughly cut to size or chewed by a dog and large exposed metal retaining clips, they are the wrong ones. Allow up to $200 to replace them depending on how much of the original assembly is missing or damaged.

To save costs, today's small cars have the wheel bearing fitted inside the brake drum when the wheel hub and brake drum should be separate. This design means that the bearings are disturbed every time the brakes are inspected. This leads to two scenarios. As the drum is dragged away from the brake shoes, the bearings can pick up dirt. If this happens, the bearings should be removed, cleaned and repacked but few repair centres do this.

The other scenario is that the little centre cap protecting the bearings from water and mud is lost or damaged during removal. Like a lid for a biscuit tin, it has to be prised off carefully but in some workshops this is regarded as a sign of weakness. Belting them off with one hit of a hammer is proof of manhood. They end up too damaged to go back on or they fall out because they are no longer round. When new replacements can be difficult to source on the spot, a service centre won't hold onto your car simply because one is missing.

I recently checked a car where its female owner had been concerned about the grease weeping from the centre of a rear wheel for two services after her wheel bearings had been replaced. Her worries were valid when this vital cap had been missing and the new bearings were filling up with water and mud. Not only do you need to check if these caps are present but they shouldn't be dented or distorted. You can usually check them just by looking behind the hubcap.

Heating and Ventilation Controls
The old way was to use a system of slides, levers and cables to change the settings of the heating and ventilation system. Although these are usually reliable, they are starting to fail on older cars. On a Porsche 911 for example, the slide control unit can cost around $800 plus a significant labour bill to fit it and that is providing you can source new parts.

Most of today's cars have eliminated the slide system and instead rely on a series of buttons to activate a system of vacuum controls powered by the engine's inlet vacuum. It's a great idea except it requires a fair amount of plumbing and a series of plastic vacuum reservoirs that ultimately crack or leak. They can be extremely fiddly to access behind the dash and replace. Again, on many popular cars including late model Commodores you can't always get the parts. Because demister function is a roadworthy requirement, who would have predicted that a plastic vacuum reservoir could force a decent car off the road?

This means that you need to check every function of the heater-demister system, with the air-conditioning on and off.

When they fail, the air-conditioning stops working. I am coming across an increasing number of used cars where a faulty switch is bypassed and the compressor is wired so it is running all the time. It will do this long enough for you to drive into the sunset but eventually the compressor and the whole car will come to a halt in a screaming, smoking mess as the compressor seizes and throws its belt.

Switch the air-conditioning on with the engine running and check under the bonnet that the compressor clicks in and out in reasonable time intervals. While you are there, check that the thermo-electric fan also kicks in and out and the temperature gauge doesn't rise excessively with the air-conditioning on.

An increasing number of cars are featuring climate control with a computer that controls the exact amount of heat or cooling to maintain a preset temperature. These computers are now failing and can be very hard to pick.

When such simple items as courtesy lights, exterior mirrors, electric windows, steering column and seat adjustment and wiper function are now fed through costly computers, it is vital that all functions are tested before purchasing a used car. If there is a warranty with a new or used car, it is also worth getting a full independent test done just before it runs out.