Guide to servicing your diesel vehicle

From ADCO.

A 16 cylinder in-line Diesel Pump at the ADCO Facility

The decision on where, when and how to have diesel vehicles serviced is something most owners of diesel powered vehicles are asked to make. The choice is to follow the ‘easy’ route of having your local technician service and maintain the vehicles. However, before taking this step, four issues should be considered, namely; technical expertise, specialist facilities, properly trained technicians and quality.

Hugo Grobler, national franchise manager at ADCO, says the difference in diesel service begins at the door of a franchised facility and the financial commitment it has made in technology. Typically, he says, this investment at an ADCO franchise could be up to R20 million or even more for state-of-the-art facilities.

‘Diesel technology, like many other technical sectors, is constantly evolving. Emission controls have become increasingly important, fuel quality has improved, and engines have been revolutionised. The best indicator of this is common rail pressures that have increased from 1350 bar in the early to mid 2000s; to more than 2400 bar today. Given the changes, spending the money to obtain the benefits from fuel economy to reliability, torque and longevity, and then taking a vehicle to a technician who can only do a basic service could be expensive in the long run.’

Clean rooms

The primary difference in quality engine maintenance lies within the facilities and diagnostic equipment available. Only specialist facilities have clean rooms where injectors, the heart of any diesel engine are finely calibrated. Add expertise in brands such as Bosch, Denso, DELPHI, Hartridge, Stanadyne, Yanmar and Zexel, combine these brands with professional technicians specialising in fuel injection and related services, and it soon becomes apparent why going to experts reaps dividends.

‘It is crucial for motorists opting for diesel power to understand that components, and not just fuel, are consumables.  Crucial parts have service intervals, and pumps and injectors should be removed, cleaned and calibrated so that the possibility of breakages and replacements is avoided,’ says Grobler.

‘Adjusting and calibrating pumps and injectors to take up wear that has occurred will ensure longer component life and performance that meets expectations. This is a basic rule of diesel engine maintenance and should be followed whether the vehicle concerned is a tractor, agricultural machine or one of the most advanced turbo diesel injection systems available. Whether they are common rail units or electronically controlled, correct maintenance is always the key to sustainable service life.’

‘One of the keys to reduced environmental emissions, reduced engine wear and reliability has been the evolution of fuel.  Sulphur is a lubricant used in diesel fuel and is vital to lubricating engine components. The reduction of sulphur in fuel has meant the addition of other additives to replace it.’


Contamination of fuel through the entry of dirt and moisture is a risk for pumps. This is why maintenance and regular inspection of this component is vital to longevity and optimal performance.

‘Older mechanical diesel systems could tolerate a small amount of contamination before requiring servicing and repair. Today, however, the differences in tolerances between the old and the new have forced a new approach. A common rail system is now running at about 2400 bar, and the tolerances involved are measured in microns. Any contamination infiltrating the system, therefore, has the potential to cause significant, or even irreparable damage. Cleanliness is essential.’

Injectors have different spray patterns and angles that are all engine-dependent — the fuel sprays from the injector into a ‘bowl’ located at the top of your engine’s pistons. Incorrect heights and timing of this spray can cause the emission of either white or black smoke from the engine. ‘Diesel that is not completely burned can then run down the side of a piston, wash the engine oil away and result, ultimately in ring and sleeve damage.’

Immediate action

Turbos, although common in most cars, are also serviceable parts, stresses Grobler. Service interval recommendations made by manufacturers should be adhered to..

‘Smoke belching from an exhaust, regardless whether it is white or black, should be regarded as a warning sign of serious things to come. Immediate action by specialists can avoid major damage and large repair bills.’

‘Diesel engines are reliable and capable of powering a vehicle for hundreds of thousands and even millions of kilometres. Like most systems, however, when it requires repair and maintenance, cutting corners and costs by not consulting specialists can end up being prohibitively expensive,’ concludes Grobler.

Fuel injection tester at ADCO

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