Common Turbo Failures
To help identify failures in warranty situations and to provide advice on how to prevent future failures occurring, the below information highlights the most common turbo failure modes.
1. OIL CONTAMINATION
REASONS
- If the oil filter is blocked/damaged or a low-quality oil filter is used
- Excess moisture can lead to premature oil degradation, increased
corrosion and wear - High carbon build-up in the engine can quickly contaminate the new oil
- Unchanged oil containing detergent deposits can become very abrasive
to the turbo’s components - Particles from carbon build up in oil feed pipes
PREVENTION
- Using fresh oil and high-quality filters helps to reduce the risk
- Replacing or cleaning the oil inlet pipes and in-line microfilters
- Take care when changing the oil during servicing to prevent accidental
contamination - Check for engine wear that could leave swarf deposits
2. OVERSPEEDING
REASONS
- Engine modifications including ‘chipping’ or ‘over-fuelling’
- The inconsistent flow of air into the turbo
- The wastegate or VNT mechanism has been set incorrectly
Worn injectors - Installing an incorrect turbo
- Loss of signal to the electronic actuator for the wastegate or VNT
PREVENTION
- Check there are no restrictions or leaks in the air intake pipe
- Ensure the wastegate or VNT linkage is operating freely and is properly
calibrated - Avoid remaps, chipping or over-fuelling
3. INSUFFICIENT LUBRICATION
REASONS
- Poor oil filter maintenance
- Insufficient oil in the sump
- Incorrect oil inlet gasket used leading to restriction in oil supply
- A damaged, blocked or low-quality oil filter
- Failure to prime the turbo with oil before the initial run
PREVENTION
- Oil supply is critical to the turbo, please ensure the oil flow is correct
- Remember to prime the replacement turbocharger with oil before fitting
- Do not use silicone on oil gaskets as it can become detached blocking
oil passages - Clean or replace oil inlet pipes to remove carbon deposits or sludge
that could restrict oil flow - Use fresh oil and new oil filters when fitting a replacement turbocharger
4. FOREIGN OBJECT DAMAGE
REASONS
- 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
or injector tips - Particles in the exhaust gas e.g. coke from poor combustion
PREVENTION
- Make sure air hoses are clear from blockages, splits and other loose
objects - Ensure no debris or engine fragments remain from the previous turbo
failure - Using new gaskets help to prevent the possibility of gasket break up
and ensure a perfect seal
5. OIL LEAKS
REASONS
Oil leaks at the compressor end:
- Blockages or restrictions to the air intake pipe, hose or air intake filter
can create a vacuum, causing the oil to leak into the compressor housing - Air leaks in the intake hoses or at the intercooler
Oil leaks at the turbine end:
- Leaks within the exhaust system
- A clogged bearing housing
- Leaks in the EGR (exhaust gas recirculation) system
Oil leaks into the compressor and turbine end:
- Repeated hot engine shutdowns leading to carbon deposits (coke) in
the centre housing - Physical damage to the turbo’s rotating parts and excessive bearing
clearance - Fitting the incorrect turbocharger
- Restrictions in the oil return pipe
PREVENTION
- Ensure air and oil drain systems are clear from blockages or restrictions
- Check the exhaust system to make sure there are no leaks present
- Ensure DPF and Catalytic converter are free of blockages
