Diesel Engine Repairs

JDM P/L possesses senior Technicians with over twenty years experience repairing diesel engines. We perform these repairs on diesel cars, light trucks and four-wheel drives.

How do most diesel engine problems occur?

We would suggest the majority of diesel problems are caused from incorrect diesel oil and poor fuel. The oil needs to be the correct specification to allow the engine to operate with the correct pressure, bad oil usually leads to low oil pressure.

These are the main catalysts for carbon building up in the engine and lead to:

  • Stretched timing chain
  • EGR valve blockages
  • Fuel system problems
  • Carbon buildup
  • Injector leakage
  • Injector pump failure
  • Engine rattle

What are the advantages of diesel engines?

By far, the biggest reason many Australian drivers are choosing a diesel is for better overall fuel economy. Diesels require a higher combustion ratio to burn the fuel, which makes it more efficient per litre.

There are other advantages to diesels:

  • Most diesels motors outlast petrol motors
  • More torque for towing and 4WDing

How does JDM P/L test diesel engines

The main tool for most Technicians is a diagnostic tool, we use one from Snap-On. We purchase a subscription to access the latest diagnostic data.

In addition to this, another tool we use is a device called a diesel compression tester if it is thought that a motor is damaged.

We use this device to do a high-pressure ratio test on the vehicle, up to 700 PSI. This will let us know about

  • Misfires
  • Leaking valves
  • Leaking rings
  • Cracks in the cylinder head
  • Crack in the engine block

We have timing tools for the timing belts for the diesels we service.

We also use a dial gauge for the injector pump. The pump supplies pressure to the injector. The injector is held shut by a spring, which is overcome by the pump producing the correct pressure rate, when the pressure is released, the injector will close. This device is worth a small fortune!

local mechanics performing servicing on an engine with a snap on testing tool

What do I need to know about oil for diesels?

There is a lot involved with oil specifications.

The most important thing is to use the oil recommended by the car’s manufacturer. The correct oil viscosity type can usually be found in the handbook. If this information is not available, JDM P/L uses a system called Autodata to identify the correct oil to use.

There are hundreds of different oils available. Each brand often makes a specification suitable for a lot of vehicles and use complex naming conventions. This can make it difficult for consumers to know what to choose.

As a rule of thumb, the number prefix represents the viscosity of the oil. Viscosity takes into account the flow rate of the oil at different operating temperatures.

Generally speaking, the lower the number of the oil, the oil will have a lower viscosity. Lower viscosity will mean the oil will travel throughout the engine more quickly and offer better cold-temperature performance.

How diesel injection systems work

Diesel EGR valves explained

Visit our EGR valve repair page to learn more.