Mazda BT-50 Problems

The last decade of dual-cab four-wheel-drive utes have emerged as the tow-vehicles of choice, and you see them everywhere filling roles exactly like the one you have planned. Popular models include the Ford Ranger you’ve nominated, Toyota HiLux, Mazda BT-50, VW Amarok, Mitsubishi Triton, Nissan Navara and Isuzu D-Max. But there are also cheaper alternatives including makes like the South-Korean made Ssangyong and various Chinese brands like LDV and Great Wall.

Just make sure you know exactly how much you need to tow before making a decision as some of the cheaper models don’t have the same outright towing capacity and even if they do, some of them don’t have the engine performance to make towing as easy as it should be. For parts availability, the Toyota would be king in really remote areas, but any of the major brands are pretty well covered in Australia.

Meantime, don’t rule out ute-based wagons such as the Ford Everest, Isuzu MU-X, Mitsubishi Pajero Sport and Toyota Fortuna. These offer better ride comfort when unladen thanks to more sophisticated rear suspensions and most have as much or almost as much towing capacity as their ute brethren.

There are many reasons for a vehicle to enter limp-home mode. One of them, of course is transmission temperature, but there are lots of things being monitored, from the temperature of the engine oil, coolant temperature, oil level and even the operating temperature of the EGR valve (which is often water-cooled in vehicles like the Mazda).

The point being that even though the transmission entered limp-home mode, the actual problem may have been elsewhere, but the vehicle’s computer believed that shutting down much of the transmission’s functions would preserve and protect the rest of the driveline. Don’t forget, either, that there are many things – a failed solenoid, low fluid level, even a faulty wiring connection or earth – that can cause a transmission limp-home event beyond actual overheating.

There’s a very simple check you can do to see whether the battery or the charging system (alternator, regulator and wiring) is at fault here. With the engine running, place the probes of a multi-meter (switched to measure voltage) on the relevant battery terminals. If you see a figure of anywhere between 13.2 and 14.7 volts, the charging system is doing its job. You might need to rev the engine slightly off idle to see these numbers, but the voltage going into the battery should be in that range.

At this point, the battery becomes the main suspect, and a worn out battery will often neither hold a charge nor accept one.

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.

An open circuit on a fuel injector is usually caused by either a broken wire to the injector, a loose terminal somewhere in the electrical circuit that drives the injector or a burned-out coil in the injector itself.

Changing the suspect injector will tell you if the coil is the problem, but if that doesn’t fix it, you’ve got to work backwards from the injector until you find the fault. Bear in mind that if the injector itself is at fault, the other three injectors might be ready to go out in sympathy. Modern common-rail engines can be hard on injectors and they sometimes need replacing before they’ve done 100,000km.

This is a really common problem with this model (and the Ford Ranger with which it shared its mechanicals). Many buyers avoid this model for this very reason. Even though many fixes have been tried it seems that this car, shown a hill and a hot day, will often overheat.

Several theories exist including that the EGR valve is the problem, as it fails and allows coolant to escape (usually into the engine cylinders). But even when the EGR valve is working properly, this engine is prone to running too hot. Some other theories hold that the thermal management of the engine itself was just underdone and there’s no real fix for it. That’s borne out by the number of people who have tried different radiators, thermostats and cooling fans and still have a vehicle that overheats.

But you could try reverse flushing the radiator and making sure than every part of the cooling system is working efficiently and properly. That will maximise your chances of not having the engine overheat but, in this case, there are no promises.

Rather than the steering completely locking up, it’s more likely you’re feeling steering that has lost is power-assistance. It can make the wheel extremely heavy and could feel as though the car won’t steer at all. This is linked to the engine stalling, because the power-steering on this vehicle is driven by a belt from the engine. No engine means no power-assistance.

The other questions, of course, are why is the engine stalling and why only on left-hand turns. There are plenty of things that can cause a modern engine to stall from a dirty fuel filter to a blocked injector or an electronic fault. And about a million things in between. An electronic scan of the vehicle might throw up a fault code that will help a mechanic unravel what’s going on.

We have heard some reports of Ranger and BT-50 (they're the same vehicle mechanically) suffering oil pump failures with fairly terminal results for the rest of the engine. The other quirk with this engine is that you can't drain the engine of oil and leave it for any more than a few minutes without the pump running dry and needing to be primed before the engine is started.

Not all mechanics know this and many a Ranger or BT-50 engine has been destroyed when the oil has been dropped from the sump and the mechanic has gone to make a cup of tea or do some paperwork. They return half an hour later, replace the sump plug, fill the engine with oil and start it up. But because the pump hasn't primed, there's effectively no oil pressure and the engine is reduced to scrap in a few short seconds.

The problem is partly to do with the different design of the pump and there are even companies that have engineered more conventional oil pumps to replace the standard units on these engines.