In most cases, diesel vehicles are more expensive to service than petrol vehicles. However, when maintained correctly, they are often designed to last longer.
Many popular diesel passenger vehicles are 4WD utilities. These vehicles often include additional components such as transfer cases and differentials, which require regular oil replacement and increase servicing costs.
Reducing Cost
Let's focus on the engine and fuel system. As most are aware, a general engine service requirement is an oil change. This involves replacing the engine oil and oil filter at regular intervals. Sticking to the manufacturer’s service schedule is critical. Delayed oil changes can increase wear, contribute to DPF issues and reduce engine life.
Air filters may require more frequent replacement in dusty or off-road conditions. Poor-quality aftermarket filters can affect fuel economy and allow contaminants into the engine. Filters should always meet manufacturer specifications. Cabin filters should also be replaced at recommended intervals to maintain air quality and protect air-conditioning components.
A diesel requires regular replacement of its fuel filter, and on some cars, they are fitted with more than one fuel filter. Some OEMs (original equipment manufacturers) may advise longer intervals between fuel filter replacements, but they also expect that owners will fill up every time with good quality diesel. Some manufacturer-recommended intervals may not account for inconsistent fuel quality. In many cases, more frequent fuel filter replacement may reduce the risk of premature fuel system failure.
Fuel Choices
Sometimes it is difficult to access quality diesel fuel. If it cannot be avoided, ask your mechanic to include a quality fuel additive in each service.
You may be interested in our article about whether diesels are more fuel efficient than petrol?
Intake Carbon Issues
One of the underlying problems we face with diesels is carbon build up within the intake system. This carbon combined with oil from the engine's breathing system can create a change in the characteristics of the induction system. If ignored it will cause poor performance, poor fuel economy and eventually has the potential to damage the engine.
This can be reduced when the vehicle is driven to suitable requirements of a diesel. This includes increasing the engine speed to around 1800 to 2200 rpm and reduce your idle time. Refer to our guide on Common Diesel Problems Explained.
Eventually, all diesels will require this to be cleaned. Mechanical removal of the intake manifold, EGR valve and EGR cooler allows proper inspection and cleaning. This should be done at regular intervals of 60-80,000km. This procedure can be labour intensive for the workshop; however, it ensures no damage will occur as a result. In return, you will have an improved running diesel, plus extended life for the engine and the environment.
The industry is aware of a quick fix carbon removal, but I strongly advise to avoiding it. We witness this damage regularly as a result of these carbon cleaning products and services.
If you're concerned about a possible blocked Diesel Particulate Filter (DPF), check out tips on maintaining your DPF.
Engine Maintenance
Additional service items include valve adjustment for some applications. This procedure is not possible on some engines as they are not adjustable, but where applicable, done regularly will reduce your long term service costs.
Final Considerations for Diesel Owners
Diesel vehicles are not necessarily cheaper to service than petrol vehicles. They often involve additional maintenance items, particularly relating to fuel systems and emission systems. However, when serviced correctly and at appropriate intervals, diesel engines are designed for durability and long-term reliability.
While diesel servicing may involve higher routine costs, neglecting maintenance is far more expensive than maintaining the vehicle correctly.
Diesel Help Australia works exclusively with professional workshops.
If you require diagnosis or repair, we can refer you to an independent workshop that is part of the Diesel Help technical support network.
Return to the Diesel Vehicle Owner’s Guide for more topics and maintenance information.
