Ask the Guide

It very much sounds as though the car's alternator has failed. The alternator's job is to charge the battery when the car is being driven. If the alternator is weak or has failed completely, it can't do that and the battery will eventually run out of charge and fail to operate things like the ignition, lights and electric power-steering. Which could entirely explain the problems you're seeing. The illuminated battery light on your dashboard is the other big hint that the alternator has quit on you.

There's a very quick check that can be done to see if the alternator is pulling its weight, and I'd be a bit surprised that a roadside-assistance mechanic didn't perform it as part of jump-starting the car to get you going. The test involves using a volt-meter to see if the battery is, indeed, being charged when the engine is running. A new or reconditioned alternator is the best solution, but only after you've tested the car to see if that's the actual problem.

You could also be looking at a battery that has failed (which, at just 12 months old, we would expect) and can also create the same symptoms you've noted.

The engines in the 2014 X-Trail were tuned by Nissan to run perfectly on 91 RON unleaded petrol. That means that if you use the more expensive Premium ULP available (95 or 98 RON) you’ll basically be wasting money. That’s because an engine that isn’t tuned for the Premium brew won’t run any better or use less fuel on PULP.

The other bit of good news is that your vehicle is also compatible with ethanol-blended petrol. That means, you can fill up from the E5 or E10 pump at the service-station and maybe save a few cents per litre in the process.

Anything is possible if you have enough money to throw at the project, but at some point, each project begins to cost more than it will ever be worth.

The real mystery, though, is how you came by a petrol-powered BT-50. In Australia, the BT-50 was sold only with a range of diesel powerplants. Petrol-powered BT-50s were made and sold in regions such as the Americas, South Africa and parts of Asia, but not here. Either that or you have a Mazda fitted with a Ford Ranger engine, as Ford did offer 2.5-litre petrol engine on Rangers from 2011 to 2015, but only on base-model, two-wheel-drive versions. That option was then discontinued.

So maybe you have a privately imported Mazda, at which point, it’s very hard to know what diesel engines will and won’t fit. The bottom line is that if you want a Mazda BT-50 with a diesel engine, the simplest thing to do is simply buy one. Chances are you’ll spend less overall than converting an existing car from petrol to diesel. Swapping a petrol engine for a diesel could involve everything from a different fuel system, wiring, transmission, differential ratios and even things like the radiator and front springs. It’s a big job.

Clutch life in most cars is determined by the type of driving you do and the type of driver you are. Cars that do a lot of urban running or towing will almost always have a shorter clutch life. Those used for highway journeys where the gears aren’t being changed as frequently tend to have longer clutch life.

But it’s also true that a driver who is gentle with the clutch and gearshift (as opposed to one who makes fast, hard changes) will also stretch the clutch’s lifespan.

I don’t think 100,000km out of a clutch is any reason to complain and suggests that you’re one of the gentle drivers out there. But before you commit to replacing the clutch, make sure that the slipping is not from poor clutch adjustment or oil on the clutch from a leaking engine seal, rather than a truly worn-out clutch. Of course, even if it is a worn oil seal (the rear-main seal is the most likely culprit) the gearbox and clutch must be removed to fix it, so a new clutch at 100,000km would be a good idea anyway to avoid having to remove all those components later for a clutch change.