Ask an expert

Why does there seem to be so many problems with the new common rail Diesel motors when they reach about 80,000 to 100,000 kms on the speedo?

The big difference between the two is the common rail engine runs very high fuel delivery pressures (up to 25,000psi) and the fuel delivery is controlled electronically in comparison to the old low pressure more mechanical system.

You don't say specifically what these problems are you have heard about, but potentially you have more to go wrong from both the electronic and fuel delivery side of things with a common rail engine.

What we do know is, common rail diesels do not like the slightest amount of contaminated fuel and the days of the farmer filling the new diesel truck from the same on-site fuel tank as the old tractor are well and truly over.

Diesel fuel is best sourced from a supplier who has a fast turnover of fuel and has clean and well sealed holding tanks.

We do understand your nervousness about these engines however, in relation to the large number of modern diesels on our roads and the reported problems, the risks are not as high as you may think.

The contaminated fuel issue is by far the biggest worry in our opinion.