Common turbo failure – foreign object damage

What is foreign object damage?

A foreign object is simply any object that enters the turbocharger through the air inlet or exhaust inlet. When a foreign object enters the turbocharger, its performance will be affected.

View our latest Melett Turbo Tips video – How does foreign object damage (FOD) cause turbocharger failure?

Welcome to our final episode in the Melett Turbo Tips series.

Today we will be discussing the causes, signs and preventions associated with Foreign Object Damage.

What is Foreign Object Damage? A foreign object enters the turbocharger through either the air intake or exhaust manifold, if this makes contact with either
the Compress Wheel or Shaft & Wheel this will impact the performance of the turbocharger.

Foreign objects can be anything from carbon particles to water. Let’s discuss the causes of Foreign Object Damage.

Exhaust gases containing particles such as coke or material fragments from a damaged engine.

Missing, damaged or low-quality air filter.

Any small particles entering though slips in the hose or rags and washes ?? that have been left there.

Exhaust gases containing particles

Missing/damaged air filter

Particles entering through damaged hoses

Items left in the intake pipe

We have discussed the causes, let’s now have a look at some of the signs of Foreign Object Damage.

The main signs of Foreign Object Damage will be noise or performance-related and you will not be able to see the damaged caused until you have taken the turbo
off the vehicle or stripped down the turbocharger.

Compressor Wheel, Shaft and Wheel and VNT will show signs of Foreign Object Damage.

Two examples of Compressor Wheels here, one with mild damage and one with extreme damage. Pitting marks caused by Foreign Object Damage is visible on the
Inducer blades.

Turbine end of the Turbocharger contains the Shaft and Wheel and the VNT, these will show signs of Foreign Object Damage.

On the VNT blades, pitting marks will be visible.

Shaft and Wheel will show damage to the inducer side of the blade, where the Foreign Object/s has entered the turbine housing.

We have a supporting PDF available on the Melett website.

Now, lets’ discuss how we can prevent Foreign Object Damage occurring to your turbocharger.

Check the air hoses are intact, in good working condition and free from blockages.

Check the air filter and always use new gaskets if possible.

If there has been a turbocharger failure or engine failure, please check the entire exhaust system is free from all fragments.

Check the air hoses are intact

Check the air filter and where possible use new gaskets

Check that the exhaust system is free from all fragments

Melett Turbo Tip – Do not assume the damage to be minor, unless you replace this turbocharger, it will continue to deteriorate and fail.

We hope you have enjoyed this series of videos surrounding failure modes. Keep a lookout for future videos from Melett and thank you for watching.
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Causes of foreign object damage

  • Small particles entering through damaged hoses
  • If the air filter is damaged (or faulty), of a low quality or missing, objects will be sucked into the air intake
  • Debris from a previous turbocharger failure
  • Broken engine components, e.g. valves or fragments of damaged piston, injector tips
  • Bolts, nuts, washers, rags or other items left in the intake pipe during servicing
  • Particles in the exhaust gas e.g. coke from poor combustion
  • Ice in low temperature conditions

Signs of foreign object damage:

  • Noise from the turbo during operation;
  • Loss of performance;
  • Chipping of compressor or turbine blades;
  • Pitting around the compressor inlet;
  • Pitting on the compressor blades.

Preventing turbo failure caused by foreign object damage:

  • Make sure air hoses are clear from blockages and other loose objects
  • Check that air hoses are intact and in good working condition
  • Ensure the air filter is the correct one for the vehicle
  • Ensure no debris or engine fragments remain from the previous turbo failure
  • Using new gaskets helps to prevent the possibility of gasket break up and also ensure a perfect seal
  • Avoid operating the vehicle without the air intake connected to the turbocharger, as rags and other workshop items can be sucked into the intake system

Please note: Never continue to operate a turbocharger with damaged blades as the rotor balance will be affected and this could impact its service life.

For further information on this or other topics, please contact Melett Technical Support – [email protected].