Mazda BT50 Common Rail pump failure

What happened?

Our customer called with a knock in his Mazda BT-50 common rail diesel. 

He sent his injectors which we found to have water contamination so we then asked him to send his high pressure pump over for inspection. 

The fuel contamination had also made it through to the high pressure pump, this created a lack of lubrication in the fuel system causing heat and friction in the pump. 

mazda bt50 pump failure

This picture shows the pump drive shaft heat discolouration from poor quality fuel


If the vehicle had continued to run with the pump in this condition the high pressure pump would most likely have seized. 

Once your pump seizes there is potential for engine damage due to the fact that there is excessive load on related components. 

How did it happen?

Poor fuel quality can come from a number of sources, some are:

  • Jerry cans
  • Fuel Drums
  • Contaminated bowsers 
  • Vehicle Fuel tanks not being cleaned when new diesel components have been fitted 
  • Biodiesel that doesn’t meet the exacting standards required by these high pressure systems

what is contaminated fuel?


How could it have been avoided?

In this particular case a waterscan kit would have alerted the driver to water being present in the fuel and if the driver was able to stop the vehicle immediately and act on the warning this fuel system failure could have been prevented. 

What's next?

For this customer, he will need a new high pressure pump, injectors, rail assembly and fuel lines as well as having his tank drained and steam cleaned. Once water has entered the fuel system it is our recommendation that all these parts be replaced and the tank professionally cleaned or the same thing could happen all over again. 

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