The extra purchase price of a diesel engine over a petrol one is only the start of the cost comparison. Generally speaking, diesels will cost a bit more to service (it depends on the make and model) and that’s if you don’t have problems with the diesel particulate filter (DPF) or soot build-up in the engine’s intake system that needs to be manually cleaned out.

You also need to consider your driving habits to decide whether a diesel is right for you. As a rule of thumb, if you don’t go for a decent drive at highway speeds for about an hour or so at least once or twice a month, then a diesel is not for you. Using a diesel engine exclusively for short trips at suburban speed can often see the DPF requiring more attention than it should, and that equals cost.

Also, modern petrol engines have really closed the fuel-economy gap that the diesel once enjoyed. The fuel consumption difference between the diesel Tucson and the petrol version is likely to be about a litre per 100km (based on the official combined figure for each). That means that even at $2 per litre (and based on the $6000 difference in price you’ve quoted) you’d need to drive 300,000km before the diesel began to pay for itself in terms of fuel saved. I’m not sure there’s a full $6000 separating the two versions of the Tucson, but even so, you get the idea.

The Hyundai brand has developed an enviable reputation in this country for reliability and quality. The brand’s warranty is also excellent, taking away even more buyer anxiety. With that in mind, the decision to go diesel or petrol comes down to the way you use the vehicle.

This applies to all brands, not just Hyundai, but if all (or most of) your driving will be urban or suburban based, then the petrol engine is for you. Yes, you’ll use a little more fuel than the diesel variant, but servicing costs could be a little lower and you’ll avoid the modern turbo-diesel’s biggest downfall; a blocked Diesel Particulate Filter (DPF).

The DPF is an emissions device that traps the soot from the diesel engine and burns it off at a later date. The problem with that is that the DPF can only burn off the soot and regenerate itself if the engine (and exhaust system) gets to a temperature high enough for this to happen. In urban running, that doesn’t just doesn’t happen, at which point the on-board computer will either try to force a regeneration (not always successful) or the DPF will have to be manually cleaned or even replaced (and that’s costly).

The bottom line, then, is that a turbo-diesel (even a modern one) is only for you if you will be driving the car at highway speeds for at least half an hour at least once a month (once a fortnight is better). If that’s how you use a car, then the diesel should be okay; if not, it’s petrol every time.