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Better fuel economy, durability, and power are the 3 top reasons why some people prefer to buy diesel engine cars, 4WDs, and trucks rather than a petrol-powered engine.

Without regular diesel engine maintenance, the fuel injection system will clog up over time, increasing the chances of a breakdown and increased repair costs.

To learn more about diesel servicing and maintenance that’s crucial to keep your diesel car, 4WD or truck running better and for longer, read on.

We’ve summarised everything you need to know about taking good care of your diesel vehicle to reduce your maintenance costs and extend the life of your vehicle.

Major Components Of A Diesel Engine

Diesel engines are also known for their ruggedness and durability.

For example, the diesel engines of Mercedes Benz hold the world record for logging 1.4 million kilometres without replacing the original engine.

Because it gives greater torque needed for hauling and pulling heavy objects, the most popular heavy-duty trucks use diesel engines.

Car manufacturers have also started to roll out Light-Duty trucks that are fitted with a diesel engine.

So what gives the Diesel Engine its power?

A diesel engine is composed of 3 sections that allow it to function properly: the Structural Parts, the Running Parts, and the System.

1. The Structural Parts – The Structural Parts provides a protective casing for the Running Parts and functions to keep the components in place.

2. The Running Parts – Functions to convert the power of combustion produced in the cylinders into keeping the engine running.

3. The System – Creates the conditions for the proper functioning of the diesel engine – supplies air, removes exhaust, turbocharging, supplies and injects fuel, and lubrication and cooling.

Here are the 6 main components of a diesel engine:

1. Engine Block – The Engine Block is made of plates and castings which are welded both vertically and horizontally to increase strength and lend more support to the engine cylinder liners, crankshafts, and heads.

2. Bedplate – This is a metal plate that forms the foundation on which the diesel engine is built. The design and construction of the bedplate must be stable and durable enough to provide support to the engine and the crankshaft.

3. Cylinder Liners – A type of bore where an engine piston moves back and forth and is made of material strong enough to handle high heat and tremendous pressure.

4. Valves – These are located on the cylinder head and are responsible for the diesel engine’s smooth functioning. It does this by regulating the flow of air/fuel mixture inside the cylinder and by exhausting gas outside the cylinder.

5. Valve Guides – A cylindrical-shaped piece of metal that conducts heat from the combustion process by processing it out of the exhaust valve and into the cylinder head.

6. Piston – This diesel engine component compresses the air/fuel mixture then converts fuel energy into mechanical energy. The power is then transmitted to the Crankshaft.

Diesel Engine Maintenance

Although diesel engines do not have distributors or spark plugs and therefore, do not require ignition tune-ups, you still need to have regular diesel engine servicing for maintenance and optimal performance. For example, the air, fuel, and oil filters need to be changed.

Even with today’s cleaner diesel fuel which no longer requires you to bleed out excess water from its system, there are still vehicles that require the water separators to be manually emptied.

It is always a good idea to have the diesel maintenance needs of your car, 4WD or truck handled by a professional mechanic as they have the diagnostic equipment, parts and accessories and the experience to do what’s required for your specific vehicle.

However, you can do your share of ensuring your vehicle stays on the road in good working condition with the following:

5 Point Diesel Engine Maintenance Checklist:

1. Check Your Coolant – A coolant is a substance that mixes with water and protects the radiator from overheating or freezing. If the coolant is not replaced, it can become acidic and can erode the radiator and other components of the vehicle’s cooling system.

2. Clean Your Engine Frequently – If dirt, dust, and grime to accumulate, it can damage a diesel engine, its component parts, and consequently affect the car’s performance.

3. Change Your Fuel Filters – Diesel engines have 2 fuel filters and it’s recommended that both fuel filters be replaced every 16,000 to 24,000 kilometres.

4. Replace Air Filters – The frequency of replacing your vehicle’s air filters will depend on the environment and climate of the areas you’re driving in. A new and/or clean air filter will help maintain the performance of your diesel engine.

5. Change Your Oil As Needed – Generally, diesel engine oil needs to be changed every 8,000 kilometres. However, if your vehicle is regularly pushed to capacity, it’s best to change the oil more frequently.

Diesel Servicing

A vehicle, whether petrol or diesel, is subject to wear and tear.

Which is why preventative-maintenance is essential, and regular diesel engine servicing should be scheduled based on the kilometres you’re doing and the conditions you’re driving in.

The only difference between servicing a diesel engine and a petrol engine is that diesel does not have an ignition system.

It is very important to pay close attention to how the fuel system is being serviced.

If not done properly, dirt and water from the fuel can damage the system.

Basic Diesel Engine Service Checklist:

Replacement of Fuel Filter – The fuel supply line of a diesel engine should have at least one filter fitted into it. The filter is disposable and should be replaced to make sure the fuel that passes through the system remains clean.

Draining of Water Trap – The fuel filter that may trap water from the fuel. This should be drained to keep the engine from misfiring.

Bleeding the Fuel System – When a new fuel filter is fitted, air can get inside the fuel system and compromise engine performance. Bleeding is a procedure which effectively removes air from the fuel system. Even if the engine has a self-bleeding mechanism, it should be bled manually to ensure thorough removal of air.

Reset the Idling Speed – If the engine is running too fast or too slow, its idling speed will need to be reset. A diesel mechanic will adjust the idle speed screw on top of the fuel injector pump.

Replace the Oil and Air Filters – To keep your engine running like a well-oiled machine, the oil and air filters will need replacing regularly. The filter casings are cleaned by a good diesel mechanic before installing the new filters. Lastly, the correct grade of diesel oil should be used for your vehicle.

Full Diesel Engine Service Checklist:

A full diesel engine service covers the same set of procedures as a petrol engine which includes the following:

  • Road Test – To assess handling conditions; determine if there are problems in steering and damage to the tyres.
  • Engine – Check the condition of the electric cooling fan, quality, and quantity of coolant, tension, and quality of alternator belt.
  • Drive System – Identify potential problems with the gearbox, clutch system, and drive shaft gaitors.
  • Electrical System – Run tests on lights, horn, battery, and alternator charging rate.
  • Steering and Suspension – Look for wear and tear; test the suspension system and working condition of the power steering system.
  • Brakes – Inspect brake pads, brake discs, and brake drums; check for damage, leaks in the brake calipers, and top up brake fluid level.

Ideally, you should have your diesel car, 4WD or truck undergo servicing every 5,000kms or 6 months, whichever comes first.

Although people love diesel cars for their fuel economy, the cost of maintaining one is slightly higher compared to petrol powered vehicles.

According to Mazda Australia, the cost of servicing a petrol-fuel Mazda CX-5 Akera is $1,561. In comparison, the cost of servicing the diesel version is $1,717.

Even though the cost of servicing a diesel engine is slightly higher than petrol, the benefits of owning a diesel vehicle far outweigh the costs of servicing it.

Diesel Engine vs Petrol Engine

Better Fuel Efficiency – If a petrol engine gets you 700 kilometres per full tank, a diesel engine will get you 1,000 kilometres.

Greater Low RPM Power – Diesel engines deliver massive power at low RPMs. You’ll cruise effortlessly on a highway at 2,000rpm while pulling a heavy trailer.

More Durable – Diesel engines are designed to withstand extreme conditions and tend to last longer than petrol engines.

Diesel Engine Oil

Diesel oil is used to lubricate the engine. Unlike petrol engines which tend to absorb tar and moisture, diesel engines take in more carbon.

Thus, diesel engine oil contains more dispersants and anti-wear additives in order to withstand extreme conditions.

There are 2 types of diesel engine oil that you can consider for your vehicle:

1. High Viscosity Oil – Affects the production of heat in cylinders, bearings, and gear sets.

Viscosity can influence the rate of oil consumption and the level in which an engine performs under different temperatures.

Before buying a high viscosity oil product, find out the correct viscosity grade from the original manufacturer.

2. Synthetic Oil – Lowers the EGT or Exhaust Gas Temperature which allows the diesel engine to run at maximum efficiency while producing less heat.

For the reason that a diesel engine burns fuel at a lower temperature compared to petrol, it is important to keep the EGT low.

Choosing the best diesel engine oil for your car, 4WD or truck can be a daunting experience. To reduce the guesswork…

5 Recommended Brands Of Diesel Engine Oil:

Castrol EDGE Euro Diesel Oil 5W-40 5L – Fully synthetic engine oil that provides maximum wear and tear protection for diesel engines. Proven to remove engine deposits that can hinder performance.

Motul 007250 8100 X-Cess 5W- 40 – 100% synthetic oil that works best with modern cars with high engine displacements and is fitted with catalytic converters and direct injection turbo diesel.

Shell Rotella 5 5001 9921-3PKT 6 5W-40 – Shell described this oil as “34% better than previous versions”. It is also fully synthetic and provides maximum protection from high and low temperatures.

Red Line 21405 – This oil works to reduce corrosion in your engine. It is ideal for light-duty trucks and is perfect for vehicles in tropical climates.

Liqui-Moly Leichtlauf High Tech – A type of low-friction oil that helps your engine run well year-round. This brand of diesel engine oil combines different kinds of base oils that can lower oil and fuel consumption.

Diesel Fuel

Today’s diesel fuels are formulated to give modern vehicles greater efficiency, a more dynamic driving experience, and top-level performance.

Over the years, diesel fuel has evolved and developed into different types that can address the needs of various cars, 4WDs, and trucks.

Here the different types of diesel fuel that you can find in the market.

Petroleum Diesel – Otherwise known as fossil diesel, this type of diesel fuel is commonly used in trains, farm and construction vehicles, and freight trucks.

Synthetic Diesel – Synthetic Diesel fuel was developed as an option for low-carbon fuel. It has been proven to reduce sulphur content and the overall level of emissions.

Biodiesel – Another alternative fuel to petroleum diesel that is produced from vegetable oils, recycled restaurant grease, and animal fats. Some of the concerns raised on Biodiesel are that it can lead to the corrosion of fuel injection component parts, trigger pump seizures, and increase the incidence of blockages.

Hydrogenated Fats and Oils – This type of diesel fuel has similar properties to Synthetic Diesel. It is produced by converting triglycerides into alkanes which helps refine and hydrate the fuel.

Dimethly Ether or DME – A clean burning and non-toxic diesel fuel that has a high cetane value that could potentially meet the carbon reduction goals of Australia.

When you get fuelled up at a diesel/petrol station, you may come up with 2 choices for diesel: Premium Diesel or Truck Diesel.

Is there a difference?

Before anything else, it is worth mentioning that the standards for the types of diesel fuel sold in Australia can be found in a document called “Fuel Standard (Automotive Diesel) Determination 2001”.

The document lists 19 physical properties that comprise the standard for Diesel Fuel in Australia.

These physical properties include the following:

  • Biodiesel
  • Sulphur
  • Cetane Index
  • Derived Cetane Number
  • Density
  • Distillation T96
  • Viscosity
  • Ash

The legislation also sets the limits for impurities at 5%.This provision means 2 things.

First, as long as your diesel fuel meets these standards, it can be used for your diesel car, 4WD or truck.

Second, the idea of a “Premium” diesel product may be more of a marketing gimmick than a truism.

The same can be said for Truck Diesel.

The only reasons you can’t use Truck Diesel for your diesel car are because the nozzle is too large to fit and it has slower volume flow.

Diesel Injector Cleaner

Your diesel car, 4WD or truck has an injector which sprays fuel into the engine in order to produce combustion.

Over time, these injectors build up dust, dirt, carbon, and debris which will prevent them from doing their job effectively.

If these injectors are not cleaned, the engine will not receive enough fuel.

Without proper combustion, the engine will not perform efficiently and your vehicle will not run efficiently, or in extreme cases, may not run at all.

How do you know that your Diesel Fuel Injector is faulty?

What are the faulty injector symptoms?

  • Poor idling because the diesel engine is not getting enough fuel.
  • The engine will tend to vibrate because the cylinder will not fire properly.
  • Problems in acceleration as the engine experiences frequent misfires.
  • The “Check Engine” warning on your dashboard lights up.
  • Noticeable fuel leaks.
  • Poor fuel economy as engine starts to demand more fuel to produce combustion.

The longer the contaminants stay the greater the probability of long-term damage to your diesel engine and its fuel system.

Fuel injector cleaners are designed to keep these types of contaminants out of the engine

Diesel Injector Cleaner Benefits:

  • Lubricates fuel system and the engine
  • Increases fuel cetane numbers
  • Restores throttle response
  • Improves cold starting
  • Eliminates engine misfires
  • Eliminates engine stutter
  • Prevents corrosion
  • Improves emission values
  • Neutralises low sulphur fuel problems

Given the importance of Diesel Injector Cleaners, there are several brands on the market.

But which ones are the best?

5 Top Diesel Injector Cleaners:

Stanadyne Performance – This Diesel Injector Cleaner has a great reputation for improving engine performance, increasing horsepower, maximising fuel efficiency, and reducing unwanted engine noises.

Power Service Diesel Kleen – A good product to use for de-clogging injectors, removing excessive deposits, and built-up gunk inside the engine.

Hot Shot’s Secret Diesel Extreme – If you’re planning on taking long drives, make sure you give your injector a thorough cleaning with this product. Hot Shot’s Secret Diesel Extreme does a great job of lubricating the engine.

Royal Purple Max-Tane – This Injector Cleaner is renowned for reducing fuel consumption. It also effectively dissolves and removes deposits in the fuel injectors, filters, combustion chambers, and valves.

Lucas Fuel Treatment – One of the most affordable Diesel Injector Cleaners in the market delivers big time in keeping your injectors clean and functioning properly.

Professional Diesel Mechanics recommend that you use a Diesel Injector Cleaner every 48,000 kilometres.

DPF (Diesel Particulate Filter) Cleaning

Have you noticed black smoke coming out of the exhaust of some diesel cars, 4WDs, and trucks?

The black smoke is caused by soot trapped in the Diesel Particulate Filter (DPF) that is being regenerated or burned off.

The regeneration happens because the DPF only has a finite capacity in capturing soot produced by the diesel engine.

DPF Regeneration Types:

Passive DPF Regeneration – The exhaust temperature increases and burns off excess soot in the filter because the vehicle is taking a long drive with sustained speed on a motorway. Taking your car on 30 to 50 minute drives is a good way to keep the DPF clean.

Active DPF Regeneration – With active regeneration, extra fuel is automatically injected whenever the filter reaches its limit. The purpose is to increase the temperature of the exhaust so it can burn off the trapped soot.

A Diesel Particulate Filter cleaner uses chemicals that reduce the level of soot emissions produced by the diesel engine. The end result is lower fuel consumption which will make the DPF last longer.

By using a DPF cleaner, you don’t have to frequently buy a new filter which can be expensive.

What other factors can lead to DPF blockage?

  • Short drives at low speeds
  • Using the wrong type of oil; some brands contain additives that can lead to blockage
  • Poor service and maintenance procedures

The third factor on the list is particularly significant.

If your diesel car, 4WD or truck is not serviced properly, it will cause your DPF to fail sooner than expected.

On average, your DPF should last 160,000 kilometres.

A qualified diesel mechanic will ensure correct servicing of your vehicle and correct DPF cleaning to reduce your overall maintenance costs and improve the safety of your vehicle.

A DPF is quite expensive. Depending on your car, 4WD or truck, the cost of a brand new DPF will range from $1,200 to $4,500 or AUS$1,800 to AUS$6,400.

Cars vs 4WDs vs Trucks – Maintenance Tips For Every Diesel Vehicle

Diesel Car Maintenance

Although it is more expensive to maintain and service a diesel engine, people still buy diesel cars for their fuel economy and overall longevity.

Therefore, if you want to enjoy the fuel saving benefit of your diesel car, make sure it undergoes regular diesel car maintenance and servicing from a professional mechanic.

Diesel Car Maintenance Tips:

  • Use quality fuel to keep your Diesel Fuel Injector in good condition
  • The diesel engine has a turbocharger that increases the amount of power that it can generate. In order to protect the turbocharger, run the car on neutral for 20 seconds before shutting off the engine. 2 minutes if you came from a long drive.
  • Ask the mechanic to run a diesel engine flush
  • Go easy when starting your car. Don’t floor-it out of your driveway first thing in the morning.

Diesel 4WD Maintenance

Owners of a diesel 4WD love its incredible power and fuel economy. A diesel 4WD is the perfect vehicle when taking the family on long drives, and when heading off-road.

Similar to a diesel car, you must take the necessary steps to make sure your 4WD remains in good running condition.

Diesel 4×4 Maintenance Checklist:

  • Replace the antifreeze every 2 years.
  • Make sure all fluid levels are topped up.
  • Check the tread of your tyres. 1.6mm is the legal minimum but this number goes up to 3mm during the winter and rainy months.
  • The cam belt should be replaced every 60,000 kilometres.
  • If the mornings are particularly cold, turn your key to 3 glow plug cycles to make sure the engine gets some extra heat. This will help you start faster and ease up the load on your battery.


Diesel Truck Maintenance

A diesel truck is the perfect vehicle for frequent pulling or carrying heavy loads. Diesel engines generate a lot of torque for greater pulling power.

As earlier mentioned, diesel engines are able to produce more power at low RPM levels. This makes ideal for long distance driving at sustained speeds.

However, a diesel truck needs to be maintained properly because it generates a lot of soot. The filters have to be regularly cleaned.

Many of today’s diesel trucks have a 2-filter system that involves a primary filter and a secondary filter.

Primary Filter vs Secondary Filter Differences:

Primary Filter – Functions to remove most of the contaminants and free water in order to protect the transfer pump. The standard for primary filter efficiency is 95% to 98% @= 10 to 50 microns.

Secondary Filter – Located between the primary filter and the fuel injection system, the secondary filter acts to remove the smallest measurable hard particles. The standard for secondary filter efficiency is 95% to 98% @= 3 to 10 microns.

Diesel fuel creates an environment of humidity that introduces water which cannot be removed. The presence of water in a diesel fuel system is a serious concern for diesel truck owners as it may lead to corrosion.

This is why diesel trucks are fitted with a water-separator filter which uses chemicals to remove water and settles them down to the bottom of the filter.

A diesel mechanic can remove the accumulated water by draining the filter during its scheduled maintenance.

With all the heavy lifting that a diesel truck does, you have to make sure it is serviced regularly.

Diesel Truck Maintenance Checklist:

  • Change the oil approx every 5,000km (if using standard oil)
  • Change the oil approx every 8,000km (if using fully synthetic oil)
  • Because a diesel truck’s turbocharger produces more soot compared to a car or a 4WD, ask a professional diesel mechanic to run a diesel engine flush whenever needed.
  • Ask the mechanic to check your oil and fuel filter frequently especially if the diesel truck is used hauling heavy objects.
  • The mechanic should likewise check your truck’s exhaust system.

Most Popular Diesel Vehicles In Australia

According to a recent study, more than 2.23 million Australians drive a diesel vehicle. Of the 2.23 million, 1.13 million live in capital cities. The remaining 1.1 million are located in regional areas.

Which types of diesel vehicle are popular with Australians?

Here is a percentage breakdown of how Australians chose their diesel vehicle:

1) 40.7% – SUV

• Mazda CX-5
• Hyundai Tucson
• Toyota RAV-4

2)  25.2% – Light Trucks or Utes

• Holden Colorado
• Mitsubishi Triton
• Volkswagen Amarok

3)  21.4% – 4-Door Sedan

• Ford Mondeo
• Volkswagen Passat
• Hyundai 130

In terms of States, New South Wales is the largest market for diesel vehicles accounting for 26.3% of sales in Australia.

Then it’s Queensland (24.9%), Victoria (23.1%), and Western Australia (14.6%).

Diesel Mechanic

Unless you’ve received a recommendation from a trusted friend, finding a reliable mobile diesel mechanic in Perth can be a challenge.

6 tips to find a trustworthy mobile diesel mechanic…

1. Make Sure the Mechanic Owns the Business

It’s a good sign if the mobile diesel mechanic owns the business and that it’s officially registered as either a business name with an ABN or a company structure with an ACN.

This means he is fully invested in growing his business and is willing to put his name on the line.

“Backyard Mechanics” are like tumbleweeds in the outback. They can be here today and gone tomorrow.

2. Prioritise Experience

If given a choice between a mobile diesel mechanic who has been in business for 3 to 5 years and one who just opened a few weeks ago, whom would you choose?

Longevity in the business should be a deciding factor in choosing your mechanic.

Those with longer experience have built a reputation and a steady clientele to keep them going for years.

3. Look For Customer Testimonials

One of the most powerful ways to qualify a good diesel mechanic is to read testimonials from past/present customers.

If available, visit his website and look for customer testimonials. Can testimonials be made up? Sure!

That’s why make it a point to ask the mobile diesel mechanic to provide the contact details of a few customers so you can verify the testimonies yourself.

4. The Right Tools

An experienced and reliable mobile diesel mechanic not only has the right tools for the job. He also has the latest tools for the job.

With today’s diesel engines incorporating more technology, a good diesel mechanic should be well equipped to handle problems with various types of computer systems.

5. Warranty On Parts And Services

If the diesel mechanic has parts replaced on your vehicle, these replacement components must carry a warranty.

Likewise, there must be warranty on service. A mobile diesel mechanic who agrees to this can be trusted because he is willing to assume part of the risk for you.

6. Professional Conduct

What are the tell-tale signs of a professional mobile diesel mechanic?

For starters, he will give you a fair quote on the spot or at least the same day if major work is required.

And he arrives at the agreed appointment time.

There are a few mobile diesel mechanics that will take the extra step and ask you to download a free tracking app so you can keep track of his whereabouts.

If you want to have your diesel car, 4WD or truck serviced, you should only have it done by a diesel mechanic whom you can trust. Otherwise, you might end up wasting time and losing money.


Diesel vehicles have developed a loyal following over the years because of their durability, power, and fuel economy benefits.

However, in order to avoid future expensive problems, diesel engines should be scheduled for regular maintenance services.

If you keep your vehicle in good condition, you’ll improve its resale value, reduce breakdowns, and enjoy lower maintenance costs.

If you’re looking for a reliable diesel mechanic in Perth, talk to us today!