Car buyers' guide: Consider mileage when choosing petrol or diesel

Mitsubishi Challenger Photo / Supplied

The dilemma

William is preparing for summer with the purchase of a second-hand SUV to tow his boat - but he can't decide between a petrol or diesel engine.

"I hear older diesels can be expensive to repair," he says. "I'm not too worried about fuel consumption as the vehicle will be used less than 9000km a year."

The Mitsubishi Challenger, Jeep Grand Cherokee and Toyota Prado have caught his eye.

Well William, a diesel engine does have a couple of clear advantages over petrol when it comes down to towing heavy loads, such as lower fuel consumption and superior engine torque at low revs. But older diesels can be expensive to repair, servicing costs more and you pay higher registration costs.

On your budget you will be looking at high mileage vehicles which will increase risk while asking prices for diesel power can be extreme.

The playing field is leveled considerably if your annual travel distance is low (less than 12,000) and towing distances short. It's only when a petrol engine is placed under load that fuel consumption rises.

A proven service history is important with proof items such as cambelt replacements have all been taken care of. Don't forget the tow bar - make sure it's up to the job in both build quality and fitment.

The budget: $40,000

The shortlist

Toyota Prado

For many this is the vehicle of choice due mainly to its reliability record. Some mechanics say this engine is more tolerant than some of the latest common-rail offerings. But you may pay more just for the badge and end up with an older vehicle with a high odometer reading.

Mitsubishi Challenger Exceed (3.0 litre petrol 2003)

The Exceed is a highly specced model which includes leather trim. Fuel consumption on the 3-litre petrol will suffer when towing. The petrol version is harder to sell, therefore should be cheaper to buy in comparison to diesels. Avoid models fitted with the petrol Direct Injection (GDI) lean burn engine.

Jeep Grand Cherokee

Certainly built to handle the most extreme conditions. However, fuel consumption and build quality for both petrol and diesel variants were definitely never its strong point. This one could also be the more expensive to own in terms of overall running costs.

Driven Recommends
If the driving is kept under 9,000km a year then the Challenger is not a bad option