Used Diesel Cars for Sale

Diesel engines are similar to petrol units in the fact they both use internal combustion as a way of producing energy.

In a diesel engine, however, it uses a compression-ignited injection system rather than a spark-ignited setup that features in a petrol. This means that the air is compressed before the fuel is injected, rather than the fuel and air being mixed before then being compressed.

This compression happens at a higher level too, allowing the air to heat up to a point that ignites the fuel spontaneously, with no need for a spark.

Diesel engines, especially on newer models, also typically have additional aftertreatments to help reduce and remove dangerous particulates. One of the most commonly used of these is AdBlue.

Diesel cars were always favoured for longer journeys, and that remains the case today. They are ideal for longer journeys because they are generally more composed and fuel-efficient sat at higher speeds than a petrol car. This is also the reason diesel vehicles are used to tow, especially when it comes to heavier trailers and caravans.

The increased fuel economy is another bonus, especially with motorway driving or at higher speeds, and this can often outweigh the increased cost of buying diesel at the pump over petrol. It’s not uncommon for diesel engines to return in excess of 60mpg in careful driving.

Diesel cars are not ideal for use solely around town and for urban trips. That’s because many newer models have something called a diesel particulate filter (DPF) that reduces harmful pollution. For this to work properly an engine has to get to a certain temperature, which shorter trips will not do. Over time, this DPF can become blocked and be expensive to fix.

They can be a cause of poor air quality, too, with the nitrogen oxide they emit being linked to health problems. That’s one of the reasons that low-emission zones (such as London’s ULEZ) have stricter requirements for diesel vehicles than those powered by petrol.