Over the years, new diesel cars have also become more and more sophisticated in technology.

One of the most interesting emerging questions for the consumer is what does the development of diesel engines mean for the wallet?

So are all diesel cars today money-time bombs and what are the most typical money-consuming repairs of diesel today?

Björn Boström, diesel expert at Diagno Oy, Heikki Parviainen, lecturer in vehicle and mechanical engineering at Metropolia University of Applied Sciences, Neste Corporation's expert group (Mattias Hellström, Terhi Kolehmainen, Markku Kuronen, Seppo Loikkanen, Jukka Nuottimäki) and Teemu Leading researcher Juhani Laurikko, Finnish Transport and Communications Agency Traficom and the Finnish Automobile Technology Association SATL are jointly responsible for this as follows:

“As with any technology, repair costs can sometimes be relatively expensive.

The more advanced the technology, the more expensive the components are generally.

This is usually also reflected in repair costs.

The components of the injection system now have to withstand even higher loads, with injection pressures already generally exceeding 2,000 bar.

At the same time, the speed and accuracy requirements for spraying technology have increased, resulting in even smaller nozzle tolerances and nozzle hole sizes, for example.

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The disadvantage of this phenomenon is that, for example, accidental refueling with even a small amount of petrol may cause starting damage, e.g.

when the lubrication of the high-pressure pump remains momentarily defective.

Sometimes the damage does not appear until much later, when the metal particles resulting from the mechanical damage have migrated to the nozzles.

Unfortunately, particles are already present in the entire system at this stage, and it is virtually impossible to remove them without renewing almost the entire system.

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Also, failure to service, such as replacing a fuel filter, often results in costly repairs for similar reasons.

Even with regular car maintenance, you can avoid unwanted surprises.

The long service interval advertised for the car does sound good, but over a longer period, engine wear and soiling are accentuated by long service intervals.

This easily results in consequential damage to the turbo as well as to exhaust gas recirculation and other after-treatment components such as the particulate filter.

In many cases, in the long run, it would be cheaper to have maintenance done a little more often than recommended.

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Today, the exhaust after-treatment system also includes components that can be expensive to replace.

To some extent, the user can influence this himself, for example by being careful not to knock the car chassis on uneven road surfaces such as a cottage road.

Of course, there are also faults that the user has little control over - regardless of technology or vehicle propulsion. ”

Source: Finnish Automotive Technology Association (2020): Questions about diesel cars - SATL experts answer.