2013 Holden Colorado Pricing and Specs

Most glow-plug systems in diesel cars work on a timer system. The manufacturer will have worked out that X seconds of current will heat the plugs to a temperature sufficient for easy starting, so that X-seconds period is where the timer will be set.

What happens, though, is that glow plugs can lose their efficiency over time (and with 233,000km on board, your car is a candidate for that to have happened). As that efficiency is lost, they don't produce the same amount of heat as they used to and, therefore, the timer isn't giving them long enough to heat the combustion chamber sufficiently. When that happens, the engine becomes hard to start. The other possibility is that the timer itself is faulty and isn't giving the plugs power for long enough. The fact that your engine starts easily after the first cold start of the day, suggests the glow-plugs are, indeed, at fault here.

The other possibility is that the car's electrical system is not sending enough voltage to the glow plugs to make them work properly. This can be verified quickly and easily with a voltmeter. This method can also verify the length of time the timer is supplying power to the plugs.

In vehicles where the timer has already shut off the power to the glow-plugs before enough heat has been generated, the solution is often a new set of glow-plugs. The good news is that these aren't expensive, nor are they difficult to change if you know what you're doing. The caveat is if you aren't sure of what you're doing, at which point the fuel system on a common-rial diesel injection system can be very dangerous to tamper with due to the super-high pressures involved.

A minor increase in noise when shifting to four-wheel-drive is quite a normal thing to happen. By selecting four-wheel-drive, you’re suddenly engaging the transfer-case output shaft, the front differential and the front driveshafts. So, fundamentally, there’s a lot more mechanical stuff happening, and that’s probably what you’re hearing.

But the change in noise shouldn’t be a huge one, nor should it involve a high-volume noise of any kind. If there’s something screeching, grinding or knocking when the vehicle is in four-wheel-drive, then there’s probably something wrong with the driveline. If the noises are loud or nasty, then you need to have the vehicle inspected to find the cause and fix it before it causes more damage.

There’s a chance that the battery is old enough that it won’t hold charge for long, so a check of the battery’s general health would be the first step here. Beyond that, conventional wisdom holds that there’s something in the car that’s staying on even though the ignition switch is off, and that’s what’s draining the battery.

But before drawing the latter conclusion, attend to the basics: Make sure the battery terminals are clean and tight and test the vehicle with the engine running to make sure the alternator is, in fact, charging the battery at the correct rate. Most tradesmen agree that something between 13.5 and 14.5 volts at a fast idle is about right for the alternator. While the voltmeter is hooked up, turn on the headlights and make sure that the alternator keeps up. If the voltage drops during this stress test, you could have a dodgy regulator.

If that all checks out, the usual suspects here become a stereo (particularly an aftermarket one) or an alarm system (ditto) that is draining the battery. Make sure that the ignition switch is, indeed, turning everything off and then go back and check the car in the dark to see if there’s a courtesy light or underbonnet light that’s still on and slowly sending the battery flat.

If nothing sticks out as being wrong, the next step would be to take to the car to an auto electrician who can use a multi-meter to check each circuit in the car individually until they find the one that’s energised when it shouldn’t be. It doesn’t take a huge current draw to flatten a battery or at least take it to the point where it will no longer start the car.

Ignoring this will not only eventually leave you stranded, it will send your battery to an early grave as batteries don’t appreciate being flattened over and over again.