The turbocharger is often perceived as being at fault but commonly the root cause of the problem lies elsewhere. Before changing the turbocharger, please make sure you have correctly identified the cause of the fault.
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Smoking |
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Impact damage caused by foreign material entering the turbine housing or compressor housing is clearly visible on the turbine and compressor wheels. Never continue to operate a turbocharger with damaged blades as the rotor balance will be affected and this could impact its service life. |
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Low
Power/Boost |
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Air inlet restriction prevents the engine from breathing as designed, this increases the engine operating temperature. An air leak in the compressor outlet, or a partially or blocked intercooler would restrict the engine breathing. |
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Noisy/Whistling |
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Often the noise comes from air/gas leakage, due to pre-turbine exhaust gas or an air/boost leaks. Check all joints - if noise continues check turbocharger clearances and wheels for housing contact. |
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Seized/Sluggish |
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If the turbocharger rotor assembly has seized or is tight to rotate, this is often due to lubricating oil degregation which can cause a high build up of carbon in the bearing housing interior restricting rotation. Insufficient or an intermittent drop in oil pressure can cause the rotor to seize, as can introducing dirt into the lubricating oil. |
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Worn/Excessive
Clearance |
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A turbocharger has specific axial and radial rotor clearances. These are sometimes mis-diagnosed as ‘worn bearings’ (See Engine manual or Holset Distributor for details). If the clearances are out of specification the cause could be attributed to a lubricating oil problem, i.e. Insufficient oil, dirt ingress, oil contamination with coolant. |
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Remember, if the root cause of the problem is not identified and remedied your problem will not go away, it will most likely just repeat itself.
