Diesel or Petrol - Which is better?

By Farzana Chaumoo

Things to consider when deciding between purchasing a car with a diesel engine or petrol engine.

One of the choices you’ll need to make when purchasing, or considering purchasing, a new car is whether you want a diesel or petrol engine. Here are some facts that will help you decide which is right for you:

Environmental Impact

Diesel engines use less fuel per kilometre, which means they emit less carbon dioxide. And carbon dioxide is largely responsible for global warming, so it makes it better for the environment, right? It’s not that simple. Diesel engines run at higher temperatures and emits more nitrogen oxide, which is toxic and responsible for the formation of acid rain and smog. Even with a catalyst, which only works when it’s hot, if the car is being used for short journeys then the catalyst never gets up to its operating temperature.

Diesel fuel also produces miniscule but highly carcinogenic particles (soot) that has been linked to breathing disorders like asthma and when lodged in the lungs, can cause lung cancer and other lung ailments.

Costs & Resale

Since diesel engines are a little more technically complex, they are more expensive than cars fitted with petrol engines. Despite this, when well-maintained, diesel-engined cars will offer a stronger resale value than a petrol car. This is, however, also changing over time as we move towards electric cars and hybrids.

In terms of maintenance, diesel engines require more regular and more pricey maintenance, but is rewarding in the long run as it’s so robust and will have a longer lifespan.

Tax

In South Africa, the carbon tax for new cars affects the price of petrol cars more than diesel ones because of the higher carbon emissions.

Driving Experience

Petrol engines are less noisy and more refined than diesel engines, but diesel engines offer more low-speed torque, which gives them more power for overtaking and towing. This also makes diesel engines better for long-distance trips and in a workhorse vehicle.

Depending on how you use your vehicle, generally diesel engines are more fuel efficient than petrol engines. But a turbo in the engine can also affect fuel efficiency, more on that here.

Which should you buy?

Ultimately, the choice between a petrol or diesel engine comes down to your driving needs and finances.
Have a look at the Best Diesel Vehicles in 2018 here.