Ask The Guide

White exhaust smoke in a diesel engine is usually the result of a fuel system problem. Possible causes are dirty, worn or leaking fuel-injectors, but a modern common-rail diesel fuel system is pretty complex, so a scan of the vehicle might be a good idea too.

Some owners of these modern diesels have been reporting very short injector lifespan, although some workshops seem to get good results with ultra-sonic injector cleaning. Even then, the problem can recur, and some mechanics reckon brand-new injectors are the only way to go.

Don’t rule out a problem with the engine’s internal seals, the turbocharger and the DPF system, either, as these can all contribute to smoke of various colours at various times.

It sounds as though the engine’s idle-speed is set a little too low, and that’s making the engine feel lumpy (because it’s almost stalling). Having the transmission in Drive is adding a little load to the equation, slowing the engine even further. There are many things that can cause this, including a stepper-motor that is faulty and not controlling the idle properly.

The best advice is to have the car scanned for a hardware or sensor fault and proceed from there. But first, try this: With the engine idling and in Drive (and the vibration present) turn off the air-conditioning. If the vibration goes away, it could be that the electronics that detect the extra drag of the air-conditioner and automatically bump up the idle, aren’t working properly.

All Australian-delivered, fuel-injected Volkswagens built after 1986 can run successfully on E10 petrol. Most E10 petrol in Australia has an octane rating of 94RON, and that’s the lowest you’d want to go. Back in the day, VW said the Jetta was better off with 95RON ULP and was not able to use the standard 91RON stuff that many cars could/can use.

The horn-beep when you lock the car should be able to be turned off via the car settings menu on the main infotainment screen. You need to the find the menu that gets you into those settings and turn off the horn beep function. Many car-owners hate this feature (and so do their neighbours) but disabling it is a fairly simple process that should also be outlined in your owner's manual.

The radio with a mind of its own is another issue altogether and has been around long enough to annoy a couple of generations of LDV owners now. Radios that turn themselves to full volume every time the car is switched on, poor reverse-camera clarity and Bluetooth systems that simply refuse to recognise some phones have all been flagged by owners. But since the car is still under warranty, you should take this up with your LDV dealer. There may be a factory reflash that will return the radio to an obedient state. Perhaps the stereo system is turning itself on automatically as it searches for a connected phone. Some LDV owners have resorted to aftermarket head units to fix these problems, but hopefully LDV has engineered a fix for these later-model vehicles.

This issue will always come down to the documented service history that each car comes with. A switched-on previous owner will not only have serviced the vehicle by the book, but will also have kept the relevant receipts as proof of this crucial work being done. We'd always choose the vehicle with a big wad of service receipts over a similar car with no (or less) evidence of scheduled maintenance.

Beyond that, the Nissan clearly has almost 50,000 fewer kilometres on its odometer, so all things being equal it probably nudges ahead at that point. In either case, the CVT transmission fitted to these cars is likely to be the major source of mechanical grief down the track. Both brands' CVT transmissions have been known to give trouble. If that bothers you, then perhaps the one to buy is the Outlander AWD with the turbo-diesel engine option. In that guise, the vehicle has a conventional automatic transmission rather than a CVT.

I'll take a punt here and suggest that your car is the turbo-diesel variant with the six-speed dual-clutch transmission. The dual-clutch unit is vastly more problematic than a conventional automatic transmission and has given many manufacturers (Ford and VW being two of the main ones) all sorts of consumer grief over the years.

The unit in your car is a wet-clutch design which is much more robust than the cheaper-to-make dry-clutch type, but has still been known to fail. (The dry-clutch units on Ford's Focus, Fiesta and Ecosport models cost Ford millions in fines when they began failing at low mileages and the ACCC stepped in.) That said, the wet-clutch units have also experienced problems, but before you scrap the car or shell out $15,000 for a new gearbox (which sounds like an ambit claim in the first place) have it checked out by a specialist. In many cases, jerky progress like you're experiencing can be caused by the transmission's control module or even a faulty speed sensor inside the unit, rather than the actual transmission hardware. If that's the case, it may be more economical to repair the car.

Beyond that, I totally agree that less than 100,000km is not an acceptable lifespan for a major component such as a car's transmission.

If the door flies open when you unlatch it, it sounds as though the problem might be with the check-strap, rather than the hinge. The check-strap has the job of limiting the amount the door can open and avoid it flinging into whatever is parked beside you. If the actual hinge was the problem, the door would almost certainly drop when you opened it, making it very difficult to close again.

In either case, though, it should be a pretty clear case of a legitimate warranty claim, and a 2020 Mazda is still well within the factory warranty period, regardless of whether you're the original owner or not.

Take the car straight back to the dealership you bought it from and there should be no arguing over having it fixed free of charge. I'm a bit surprised a car dealership would sell a car with this sort of problem, but it might simply be that the item was overlooked when the vehicle was being prepared for sale. The bottom line is that this is Mazda's problem, not yours and according to the warranty, it should be fixed for free. The only exception to that would be if the damaged part was caused by previous crash-damage, but even then, the second-hand car warranty offered by the dealer should cover such a pre-existing problem.

The 2.5-litre turbo-diesel engine fitted to the 2010 Triton uses a toothed rubber timing-belt which requires periodic replacement. Most mechanics reckon the belt should be changed every 100,000km and because of the design of the engine, the belt that drives the engine’s balance shafts should also be replaced at the same time.

This is not an uncommon complaint with MU-X owners nor the owners of many other makes and models. It seems as though some Bluetooth systems prefer an Apple phone to an Android and vice-versa. The solution for some owners has been to change their brand of phone, but that seems pretty extreme. Others have resorted to aftermarket Bluetooth systems, but since your car is still brand-new, it doesn't make sense to be changing the head unit.

The first thing to do is contact Isuzu to see if there's been a new download to reflash the head unit and improve the Bluetooth performance. Car makers constantly chase this stuff, and a reflash might suddenly make the thing play the game properly.

You can check whether the problem is phone incompatibility by trying to pair somebody else's phone (of a different type) to see if it works properly with the MU-X's system.

The trade recommends a fully synthetic oil for either the diesel or petrol engines of the Golf Mk 7. The correct grade and specification is 5W30 which will give you maximum engine protection and performance.

The other engine-oil recommendation for this car is to not skimp on checking the oil level with the dipstick. These engines – in particular the 2.0-litre petrol unit – are designed to sip a little oil between changes, so don't be caught out with too little oil in the sump as that can cause catastrophic damage to the engine. The engine does this because it's a low-friction design, but the small amount of oil you'll use will be more than offset by the fuel savings engines designs like this can deliver.

Make it a habit to check the oil level every Saturday morning; it's a simple thing to do and something that we all once had to do in the old days when most engines burned a little oil.