Ask The Guide

First things first. Your daughter’s car came with a five-year warranty. That warranty will have started when the car was first registered. So job one is to see if it’s still within that five-year/100,000km window and, if it is, make this Mitsubishi’s problem. Even if the car is slightly out of warranty, if it’s been serviced properly, you might find Mitsubishi will meet you part-way with the cost of repairs.

Beyond that, the touch-screen function has either failed or the unit has experienced a moment of electronic confusion. See if there’s a reset function for the head unit and if there is, perform the reset and see if it comes back to life. The other thing to try would be to disconnect the car’s battery for at least ten minutes and see if the screen recovers when you reconnect the battery.

The biggest issue owners have experienced with this car is a tendency for the engine to consume oil and require a top-up between oil changes. Holden addressed this by changing the specification of the oil from a 5W30 to a 5W40 oil and released a new oil cap design. You’ll know if the new-design oil cap is fitted to your car as the owner’s manual will have been altered by a Holden dealer to reflect the new oil specification.

Beyond that, the biggest driveline complaint seems to be the noise generated by the engine. However, this seems to be a natural by-product of the 2.8-llitre turbo-diesel fitted to the Colorado 7 and is not a fault per se.

The car could be trying to trying to tell you that there’s something wrong with the key. So start with the basics. The most common cause for the key to not operate the ignition and security system (which is why the engine won’t start) is because the key’s battery has gone flat. Change it and see if that works. At the very least, try the second key (that should have come with the car) to see if it will operate things properly.

If not, then you have to start digging deeper, at which point the cause could be a glitch within the car’s body computer which is the brain that controls everything from the power windows to the central locking and immobiliser. If that’s the case, then an auto electrician is probably your best bet, but definitely check the key’s battery first.

These older Mercedes sedans are seriously under-valued given what they represent. The price of a decent house when new, they’re now available for very reasonable sums, and they represent a lot of car for the money. Provided you get a good one. Because a crook one will bankrupt you.

The car you’re looking at is from the later, facelifted W124 series and the reason it’s had a new wiring harness fitted is because this model suffered form a new type of wring M-B was trialling at the time which turned out to literally fall to bits over time. But the replacement harness should not have the same problem, so that’s in this car’s favour.

The kilometres are also pretty low for a car like this, so I’d say that price, with a RWC thrown in, is a pretty sharp deal and represents good buying. On two conditions: That there’s some evidence of a service record that doesn’t have big gaps suggesting skipped maintenance, and that you carefully test drive the car and make sure you can live with its habits. These old Mercs tend to take off in second gear (they’re designed that way) and, with the four-cylinder engine in this example, you won’t want to be in a hurry. Beyond that, however, a good W124 is a true delight.

The MG 3 has a wheelbase of 2520mm, compared with its overall length of 4055mm. That puts it (on size) somewhere between the likes of popular hatchbacks, the Toyota Corolla, and its smaller brother the Yaris.

There are many, many things in a modern cat that can cause the check-engine light to illuminate. The cause could be anything from a sensor somewhere on the engine or in the exhaust to a problem such as low oil pressure, overheating, a dud fuel-injector or even a stretched timing chain that has allowed the crankshaft and the camshafts to become out of synch.

Basically, the car’s computer notices and logs anything that’s amiss and warns the owner that some form of servicing is required by lighting up the check-engine light. The other possibility, of course, is that whoever worked on the emissions control system you mentioned, may have neglected to manually turn off the check-engine light. It’s happened before.

The most common cause of this sort of vibration is usually an unbalanced front wheel and tyre, especially if the problem began suddenly. When new tyres are fitted, they are balanced at the tyre shop by adding small weights to the rim to literally balance the wheel and tyre assembly. But these little weights can fall off over time (or if you’ve smacked a kerb or pothole) leading to an unbalanced wheel. At which point, a vibration can set in. And since you’re feeling it through the steering, the suspicion would be that it’s a front wheel at fault.

A tyre shop should be able to check this for you and rectify the problem for a reasonable cost. If this is not the problem, then you need to start looking deeper into the suspension and possibly even the brakes. But don’t rule out a bent or damaged rim given the parlous state of this country’s roads right now.

You should be guided by your mechanic’s quote for either outcome. In some cases, solenoids are relatively cheap to buy and don’t require too much labour to replace. But, depending on the vehicle, they can also be very expensive and require more or less a full transmission strip-down to remove and replace.

You also need to assess the condition of the whole transmission as putting new parts into a worn gearbox will only delay the inevitable.

If this was an older car, the explanation would be simple: Cars always have at least a driver on board, but sometimes only a driver. Which means that the driver’s seat gets worn out faster than any other seat in the car. But you car is quite new, so that shouldn’t be the case.

Assuming there’s no manufacturing flaw in the seat or the way it’s mounted, the cause of this could be as simple as a driver’s seat that has more adjustments available (manual or electrically-operated) than the front passenger’s seat. If that’s the case, you might find that the mechanics of those adjustments gobble up some space that is used for foam or other padding in the not-so-adjustable passenger’s chair.

Run-flat tyres were the car companies’ way of making more luggage space and cutting cost from each car. But they had their problems including the noise you’ve mentioned as well as a lack of ride quality. Although, to be fair, the latter has improved massively in recent years with new generation run-flats hitting the market.

A good tyre specialist should be able to advise you on which run-flats are the current favourites in terms of noise and ride, as well as grip and price. But it’s worth mentioning that tyre manufacturers are constantly trying to outdo each other, so the improvements keep coming. The best tyre today might not be the best one in a few months’ time.

The concept of a larger (wider) tyre on the rear of your car is to do with grip and handling. Messing about with this relationship could lead to a less athletic car and there are physical limits on what tyre can be fitted to what rim.

You could make the switch to a non-run-flat tyre and buy a tyre repair kit to keep in the boot. In fact, many owners of earlier cars with run-flat tyres have done just that. You still stand to pick up a little ride comfort by doing so, but nowhere near as much of an improvement as you would have, say, a decade ago.