turbocharger failure analysis 3-09
DESCRIPTION
testTRANSCRIPT
-
Turbocharger Failure Analysis
Gus Wright
-
Symptoms of Turbo Failure1. Low or no boost (Performance complaints)2. Noise3. Oil leakage4. Poor transient response (i.e Lazy lag) 5. Blue smoke6. Fault codes 7. Excessive combustion temperature (i.e. Heat
damaged cylinder components, exhaust manifold and exhaust pipes)
Causes of turbocharger failure varied
-
Verifying Performance Complaints Must road test or use dynamometer to
verify low power complaint.
Intake boost pressure which meets minimum specifications generally means the turbocharger and engine are performing satisfactory.
-
Low Boost = Low-power Boost pressure gauge
No/low fuel = no boost.
Restricted air flow = poor combustion and low-boost
-
Sources of Noise
Bearings & Leaks
-
Noise Some turbochargers will create unusual noises during acceleration.
Warble or (Woofing or barking during deceleration) is commonly caused by surge when the compressor wheel speed is unable to correctly move air due to aerodynamics of the housing.
-
Bearings Coked
Coked bearings caused by hot shut-down.
Causes contact of rotating compressor or turbine wheel with turbo housings
-
Bearings
Bearing damage due to hot shut down
-
Pre-lube Turbo Bearings!
-
Inspecting Turbo Bearings
Up & Down radial play.
In & Out Axial play
-
Bearing Inspection
One technique for measuring radial movement
-
Axial End-Play Measure
-
Turbine Shaft Damage
Hot shut-down
-
Compressor Wheel Damage
Note difference between damage caused by hard and soft objects
-
Compressor Wheel Damage
-
Over-speed
-
Oil leakage
Oil leakage is not acceptable.
Too much idling, High crankcase
blow-by pressure
Worn/damaged seals
-
Oil leakage 1 All turbos wisp some
oil. Crankcase oil is
drawn into turbochargers of some closed crankcase systems.
Intercooler hoses weeping oil
-
Evaluating Oil Leaks
-
Turbine Seal Damage
Missing oil seal
-
Turbine Oil Seal