Isuzu MU-X Problems

This is an annoying but relatively common problem in many cars, not just the Isuzu. Because a car’s air-conditioning system dehumidifies the air (as well as cooling it) the water that was suspended in the air has to go somewhere. When everything’s working properly, there’s a small drain-hose from the air-con unit, through the floor to under the car where the water can be dumped with no problems.

But what often happens is that the little tube or drain-hose becomes blocked. At which point, the air from the atmosphere has nowhere to go other than inside the cabin where it causes the mayhem you’re experiencing. By locating the drain-tube and cleaning it out, the problem should go away. If not, you need to look more closely at the car’s heater matrix which also lives under the dashboard and can leak coolant into the cabin for a similar range of problems.

Air-conditioning relies on fans as well as the actual refrigeration system to move the chilled air around the cabin. If the fan isn’t working, that won’t happen. So a check of the fan in question would be a good place to start. Perhaps there’s a wiring fault, maybe the fan is intermittently failing to kick in.

There’s another possibility, too, and it’s more common than you might think. Some air-con systems tend to build up ice inside the system’s plumbing. If that happens, you’ll suddenly get no air-con and possibly even zero airflow through he vents as the ice blocks the trunking completely. The solution is to turn the system off at that point, allow everything to thaw and then turn it back on. Try that process next time the vents fail to see if that fixes it (temporarily).

My experiences with the very latest turbo-diesel engines available suggests that DPF burn offs are being programmed to happen much more often. It’s likely to be a manufacturer response to the problems associated with DPFs that become clogged and then require manual cleaning or even costly replacement. By programming the DPF to burn off more often, the theory is that this will lead to fewer DPF blockages and other problems, making life easier for the car’s owner and reducing customer complaints.

Perhaps another aspect of this is that the DPF burn usually takes several minutes and kilometres of driving to complete. If the vehicle is stopped before the burn is complete, it may try again for a complete regeneration (burn) as soon as possible, which could be why you’re seeing these frequent notifications on the dashboard.

Unlike some newer cars which use an electrically-operated park brake, this model Isuzu has a conventional, mechanical park brake set-up. So that’s a good start as the mechanical version is much simpler.

The tiny switch that is operated by the park brake lever (and lights up the warning light) can often fail or short-circuit, leaving the car thinking that the park brake is still applied even though it’s not. But if you’ve gone to the trouble of changing the wiring to the park brake lever, then presumably this switch was replaced, too. Or at least checked.

So the next thing to do is to make sure that the park brake is, indeed, releasing completely when you lower the park brake lever inside the cabin. If the park brake is poorly adjusted, you might find it’s not releasing all the way, and that’s what’s causing the problem. A quick squirt of contact cleaner on the switch would be your first move, however.

Rule of thumb says the correct on-road pressure is somewhere between 30 and 40psi for tyres like these. But since you’re losing traction regardless of inflation pressure, who knows. Clearly something else is going on here. Just for starters, the MU-X is fitted with both traction control and stability control which should rule out losing traction in the first place. Are these systems working? If not, you’re technically driving an unroadworthy vehicle.

How old are the tyres? Were they fitted to your previous vehicle and swapped over to the new one? Tyres have a finite lifespan beyond which the rubber compound starts to degrade and the tyres lose grip. That’s something to check. Perhaps the rubber has been contaminated by something like oil or grease. Has the vehicle ever been parked in a pool of oil or diesel? It sounds pretty daft, but is the fuel tank or filler neck allowing diesel to leak on to the tyres or flick up on to them as you drive?

You also need to be aware that as an off-road tyre, on-road grip will never be as good as a tyre designed to work mainly on bitumen. The tread pattern and compound are both compromises in the interests of going off-road, so you can’t expect passenger-car tyre grip from a tyre like this one on a vehicle like your Isuzu.

This make and model of tyre seems to be pretty well received among users, although some have mentioned a lack of wet bitumen grip as something to keep in mind. Don’t forget, either, that in really wet or greasy conditions, you can safely switch to high-range four-wheel-drive to prevent wheelspin and improve your safety margin.

Australian dust is pretty amazing stuff. In some locations, it’s so fine, it can get past even the best rubber seals and into a car’s cabin. Problem is, once it's found its way into the heating and cooling plumbing on your car, every time you turn on the climate control or open the vents, you’re going to smell dust.

Cabin filters can help reduce this, but once the dust has entered the car, there’s very little chance of ever removing it completely.

However, if the smell is only present when you’re travelling on a gravel road, it might be that there’s a more obvious leak that is allowing the dust inside at that point in time. Check all the door and window rubbers, not forgetting the tailgate as the rear of the car is where the dust often enters.

If there are no rubber seals showing damage (or a tell-tale trail of dust) make sure each panel is properly aligned and that the weight of a spare-wheel rack (if you have one fitted) hasn’t distorted the tailgate hinges.

The other thing to do is to put the climate-control on recirculate and switch on the air-conditioning as this will pressurise the cabin and help keep the dust from being sucked into the car. It’s amazing how effective this can be.

This is an increasingly common complaint among car owners who are finding that modern driver safety aids such as autonomous emergency braking and lane-keeping assistance programs are too sensitive and don’t take into account the whole picture at the time. Examples include shrubs in a driveway causing the emergency braking to activate, and lane-keeping assistance trying to maintain a car in the centre of its lane despite a looming wide-load on a truck next to it.

I’m not sure what the solution is. But we can only hope that as cars get better and these programs more sophisticated, the errors won’t be as common. But while ever this tech relies on a computer and an algorithm, it will be doomed to (sometimes) fail. This is one of the reasons completely self-driving cars are not yet a reality on our roads; the tech is simply not foolproof yet.

Meantime, covering your car’s cameras with tape might put a stop to the false alarms, but it might also create new problems as the computer searches in vain for the camera’s input. And your concerns about insurance hassles are well founded, too. It’s not hard to imagine the owner of a car with disabled safety features being refused cover in the event of a crash.

Okay, here’s the bottom line: All engines use a little bit of oil. If they don’t there’s either something wrong with the oil pump, or the owner is kidding themselves and not checking the oil level correctly. Modern turbo-diesels also 'breathe' a little oil back through the engine as part of the emissions control system, and owners with an aftermarket catch-can system often find a bit of oil winds up in there instead of being burnt in the engine.

The question is how much is too much. I don’t think 700ml per 2000km is excessive and your dealer’s views will be based on the official figure from Isuzu. But in the real world, owners are reporting oil consumption of around a litre to 1.5 litres per 5000km. At which point, your engine is right on the money.

How you drive the vehicle and whether you tow a heavy load will also affect oil consumption, as will ambient temperature and the type of oil you use. It’s a fact that modern, lower-friction engines are designed to use a little oil in the name of saving fuel, and it’s something car owners need to get their head around. Keep an eye on that dipstick and you should be fine. Checking the oil on a regular basis will also tell you whether the engine’s drinking habits have changed; a much more valuable piece of knowledge to have.

This is probably a simple case of an automatic transmission doing what it’s designed to do. In order to keep the engine in its comfort zone (and making sufficient power and torque to haul the caravan at the speed you’ve chosen) the transmission will shift through its gears to achieve that happy balance.

Any time you encounter a hill or even a headwind (and it’s more so with a heavier caravan) the transmission will assess what speed you want to hold, and then (via changing gears) keep the engine at a speed that supplies the necessary performance. Even a hot day can cause a change in the shift patterns as the transmission aims to take the strain off the cooling system by giving the engine and easier time. Again, a big, heavy caravan will amplify this effect.

However, if the transmission is changing gears for no apparent reason, then you may need to have the calibration checked and perhaps even reprogrammed. Don’t forget, though, that a modern transmission is a pretty clever piece of gear that can even choose to shift down gears going downhill to take the strain of the vehicle’s brakes. Don’t confuse an active transmission with a dud one. And if you still think the behaviour is odd, then an electronic scan of the vehicle might provide more information.

I’d be interested to know what happens after the 30 minutes when the system switches itself back on. Does it disable again if you give the connecting plug a wiggle? If so, it’s probably a poor electrical connection somewhere inside the plug assembly. If you need to turn the ignition off and back on to make the system disable itself again, then you might be dealing with some kind of computer (body computer?) problem.

The thing is, if this is a genuine Isuzu accessory option, then it should come under the car’s new-car warranty. At which point it’s Isuzu’s problem to fix, regardless of whether the dealership you use has seen this issue before or not.