Since the birth of the turbocharger in 1905, its popularity and use has grown every year. From being used in aviation to help make up for power loss at altitude, to diesel engines on passenger transport ships to use in diesel/gasoline powered automobiles they can be found everywhere. Turbochargers even helped the US Army Air Corps B-17 and B-24 bombers to degrade the German war machine in WW2. You might say using spent exhaust gas energy to build speed and power is as American as it gets.
So no shit, there you were, lined up with (insert V8 domestic sports car) at the light. Tune set to kill, 4WD Hi and brake boosting everything your converter can hold ready to take that weak no turbo car to gapplebees. Light turns green and you're gone with massive surge of torque and as you're leaving the competition behind you hear a huge change in engine noise, an audible pop might be heard, power falls on its face and then some smoke you weren't expecting. Your turbo has called it quits, but why? That's what we're going to talk about in this article. How to diagnose turbocharger failures and how to prevent them. (This is not by any means an all inclusive list of every possible cause of failure or every possible symptom but rather good guide to the most common failures)
So first things first, how do you even know your turbo is failing? Well there are a ton of possible symptoms and causes
COMMON FAILURE SYMPTOMS AND POSSIBLE CAUSES
When it comes to obvious symptoms, BLACK SMOKE is easy to spot. Some causes of black smoke can be:
Boost pressure control swing valve/poppet valve/VGT-VNT vanes sticking/not closing
Dirty air filtration system
Dirty compressor or intercooler system
Air filter housing cracked/missing gaskets or loose connection
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Foreign object damage on compressor or turbine wheel
Fuel system defects or incorrectly calibrated
Poor oil supply to turbocharger
Intake and charge air system bent/loose or incorrectly installed
Turbine housing or wastegate/VGT-VNT system damaged
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
BLUE SMOKE from the exhaust is another symptom that can signal turbocharger harm.
Coked oil and sludge in turbocharger center housing
Crankcase ventilation clogged and distorted
Dirty air filtration system
Dirty compressor or intercooler system
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Oil feed and drain lines clogged, leaking or distorted
Piston ring sealing defective
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
TURBOCHARGER GENERATING HARMONIC NOISE can be a good indication of impending doom.
Dirty compressor or intercooler system
Air filter housing cracked/missing gaskets or loose connection
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Exhaust leakage between turbine outlet and exhaust pipe
Foreign object damage on compressor or turbine wheel
Poor oil supply to turbocharger
Intake and charge air system bent/loose or incorrectly installed
Turbine housing or wastegate/VGT-VNT system damaged
Turbocharger bearing damage (results in slow response and insufficient airflow)
OVERBOOST CONDITIONS may be noticed if you have display of some kind. (OEM gauges, aftermarket gauges or OBD2 monitor)
Boost pressure control swing valve/poppet valve or VGT-VNT vanes sticking
Fuel system defects or incorrectly calibrated
Pipe assembly to swing valve/poppet valve or VGT/VNT actuator defective
A DEFECTIVE COMPRESSOR/TURBINE WHEEL can also result in substantial damage/cost
Excessive exhaust gas temperatures (fueling or aftermarket calibration related)
Foreign object damage on compressor or turbine wheel
Poor oil supply to turbocharger
Turbine housing or wastegate/VGT-VNT system damaged
Turbocharger bearing damage (results in slow response and insufficient airflow)
OIL LEAKAGE AT TURBINE is one of the more covert and gradual killers of turbochargers
Coked oil and sludge in turbocharger center housing
Crankcase ventilation clogged and distorted
Oil feed and drain lines clogged, leaking or distorted
Piston ring sealing defective
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
HIGH OIL CONSUMPTION can be another indicator if you're proactively checking fluids
Coked oil and sludge in turbocharger center housing
Crankcase ventilation clogged and distorted
Dirty air filtration system
Dirty compressor or intercooler system
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Oil feed and drain lines clogged, leaking or distorted
Piston ring sealing defective
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
UNDERBOOST CONDITIONS and LOW POWER can be good indications of failure
Boost pressure control swing valve/poppet valve or VGT-VNT vanes sticking
Dirty air filtration system
Dirty compressor or intercooler system
Air filter housing cracked/missing gaskets or loose connection
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Foreign object damage on compressor or turbine wheel
Fuel system defects or incorrectly calibrated
Poor oil supply to turbocharger
Pipe assembly to swing valve/poppet valve or VGT/VNT actuator defective
Intake and charge air system bent/loose or incorrectly installed
Turbine housing or wastegate/VGT-VNT system damaged
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
DIAGNOSTIC TROUBLE CODES and CHECK ENGINE LIGHT
U010C - Lost Communication with Turbocharger/Supercharger Control Module
This code can be caused by a dead battery, faulty VGT-VNT turbocharger actuator controller or a general CAN bus communication failure
P0045 - Turbocharger/Supercharger Boost Control Solenoid Circuit Open
This DTC can be seen as a result of a dirty air cleaner, vacuum leaks at the manifold/intake horn, failing MAP sensor and/or loose connections between turbo/exhaust manifold, intake piping/turbocharger or a failure of the turbo by internal oil/coolant leaks
P2262 - Turbocharger Boost Pressure Not Detected-Mechanical
This trouble code typically manifests as a loss in engine power and may require replacement of the turbocharger actuator, the turbocharger as a whole or an inspection of the wiring harness leading to the actuator (looking for chaffing or damage)
P0299 - Turbocharger Underboost Condition
This code can be realized from a faulty turbocharger, damage to the EGR system, air leak or restriction in the intake/charge air system or a faulty MAP sensor
The last symptom is OIL LEAKAGE AT COMPRESSOR
Coked oil and sludge in turbocharger center housing
Crankcase ventilation clogged and distorted
Dirty air filtration system
Dirty compressor or intercooler system
Excessive exhaust back pressure from clogged filter/muffler or leakage upstream of turbine
Oil feed and drain lines clogged, leaking or distorted
Piston ring sealing defective
Turbocharger bearing damage (results in slow response and insufficient airflow)
Valve guide, piston ring or cylinder liners are worn with increased blow by (this can introduce engine oil to the turbocharger through the PCV/CCV system)
Before we get into the pictures of failures and discussion, it is important to note that many of these failures can be prevented by simply conducting maintenance on a regular basis. Turbochargers truly only need a few things to be successful, this includes the following:
High quality oil and oil filters
Inspect/change your oil and oil filter on time
Monitoring your oil level with periodic checks
High quality engine air filter
Inspect/change your engine air filter
Monitor the cleanliness of your engine air filter
Inspect/change PCV/CCV filters (if equipped)
Now to the failures:
DIRTY AIR FILTRATION SYSTEM
(Even with an OEM quality air filter, failure to service/inspect the filter has resulted in an oil soaked/dirty air filter that produced so much restriction to airflow that the turbo deformed the filter element and the mesh structure which resulted in debris being drawn into the turbocharger/engine)
FOREIGN OBJECT DAMAGE
This is a great example of catastrophic turbocharger failure caused by an introduction of a foreign object to the compressor wheel. Whether it was environment or part of your air filter being ingested this is likely to produce a loss in performance as well as potential for audible sound
DAMAGE TO COMPRESSOR OR TURBINE WHEEL
Damage to the compressor or turbine wheel in this image is due to the wheel contacting the housing. This can be the result of turbocharger bearing failure caused by poor oil supply, poor tuning/faulty hardware that overspeeds the compressor or excessive exhaust gas temps.
TURBOCHARGER BEARING FAILURE AND SHAFT FAILURE
Bearing failure is a big killer for turbochargers, this can be fed by poor oil supply or excessive exhaust gas temps which weaken the material as well as causing accelerated degradation of the oil and it's ability to produce a lubricating anti-wear film across components.
POOR OIL SUPPLY OR CONTAMINATED OIL
Inability to supply the appropriate volume of high quality clean engine oil to the turbocharger is a surefire way to reduce the service life of your turbocharger. Poor oil supply can be manifested on the turbocharger parts visually as seen below.
Material transfer from journal bearing
Discoloration of journal bearing diameter of the shaft
Excessive wear to thrust bearing
Scoring to journal bearing diameter of the shaft
Scoring to thrust parts
Scoring to journal bearings
COKED OIL ON TURBOCHARGER CENTER HOUSING
Coking and sludge build up can be caused by poor oil supply or poor quality oil.
EXCESSIVE EXHAUST GAS TEMPERATURES
This turbine failure was the result of excessive exhaust gas temperatures which caused a material failure during these extreme speed/temperature conditions.
Turbine housing damage though rare is a devastating byproduct of excessive exhaust gas temperatures. These temps can result from excessive fueling and poor exhaust gas flow.
COMPRESSOR FAILURE
Compressor failure of this nature is typically caused by a turbocharger overspeed condition. This type of failure can also destroy the compressor housing while introducing substantial contamination to your charge air system, oiling system and potentially damaging or killing those near by.
We hope to have provided you with a way to maintain, diagnose and understand common turbocharger failures and their causes. If we can assist you with supplying fluids, filters or any guidance on care or use of your turbocharged vehicle we're happy to do so.