Hyundai Sonata LF Quiz
Engine Mechanical System

Turbocharger Repair Procedures

In this manual: Engine Mechanical System
General Information — 9Engine Mechanical System — 90Engine Electrical System — 58Emission Control System — 24Engine Control System/Fuel System — 114Drive Shaft and Axle — 15Suspension System — 35Steering — 19Restraints — 50Brake System — 54Body (Interior and Exterior) — 213Body Electrical System — 241Heating, Ventilation, and Air Conditioning — 56DCT (Dual Clutch Transmission) System — 52
15steps
~90min
4/5difficulty
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Inspection on Vehicle

Turbocharger Diagnostic Flow

If any problem related to the turbocharger occurs, such as insufficient engine power, poor acceleration, abnormal engine noise, or oil leakage, inspect the turbocharger according to the following procedure.
  1. Check the turbocharger assembly and the exhaust pipe (or aftertreatment device) assembly.
    A. Check that the gasket is installed.
    A. Check that the mounting bolts (or nuts) are tightened correctly.
    A. Check for gas leakage.
    A. Check the parts for damage, such as cracks.
    If exhaust gas leakage occurs because a gasket was not installed or the mounting bolts (or nuts) were not tightened properly, it may cause engine noise. If the cause of the problem is found, retighten the mounting bolts (or nuts) to the specified torque, or replace the gasket or damaged parts with new ones, if necessary.
  2. Check the exhaust manifold and cylinder head assembly.
    A. Check that the gasket is installed.
    B. Check that the mounting bolts (or nuts) are tightened correctly.
    C. Check for gas leakage.
    If exhaust gas leakage occurs because a gasket was not installed or the mounting bolts (or nuts) were not tightened properly, it may cause engine noise. If the cause of the problem is found, retighten the mounting bolts (or nuts) to the specified torque, or install a new gasket if necessary.
  3. Check the turbocharger oil supply pipe and hose, and the oil drain pipe and hose.
    A. Check that the gasket is installed.
    B. Check that the mounting bolts are tightened correctly.
    C. Check that the clamps are in place.
    D. Check the oil pipes and hoses for damage (kinks, crushing, tears, or cracks).
    If exhaust gas leakage occurs because a gasket was not installed or the mounting bolts were not tightened sufficiently, it may cause oil leakage. If the oil supply pipe and hose are damaged, engine oil is not supplied sufficiently to the turbocharger, which may cause turbocharger damage. If the oil drain pipe and hose are damaged or clogged, engine oil drains unevenly, which may cause oil leakage from the turbocharger. If the cause of the problem is found, retighten the mounting bolts (or nuts) to the specified torque, or replace the gasket or damaged parts with new ones, if necessary.
  4. Check for oil leakage between the center housing and the compressor housing.
    A. Check that the mounting bolts are tightened correctly.
    B. Check for oil leakage.
    If the O-ring (gasket) between the center housing and the compressor housing is damaged, it may cause oil leakage. If oil leakage is detected, replace the turbocharger with a new one.
  5. Check the turbocharger actuator.
    A. Electronic actuator: Check the movement of the actuator rod while performing the actuator forced operation using the GDS. (Refer to the Diagnostic Trouble Code guide)
    If the turbocharger actuator is damaged, it may cause insufficient engine power and poor acceleration. If the actuator rod does not move, replace the turbocharger with a new one.
  6. Check the turbocharger compressor wheel.
    A. Check that the compressor wheel is not damaged (bent or deformed).
    B. Check that the compressor wheel rotates smoothly. (Refer to the Turbocharger Inspection)
    If the compressor wheel is damaged, it may cause abnormal turbocharger noise and poor acceleration. If the compressor wheel is damaged or deformed, replace the turbocharger with a new one.
  7. Check the turbocharger turbine wheel.
    A. Check that the turbine wheel is not damaged.
    B. Check that the turbine wheel rotates smoothly. (Refer to the Turbocharger Inspection)
    If the turbine wheel is damaged, it may cause abnormal turbocharger noise and poor acceleration. If the turbine wheel is damaged or deformed, replace the turbocharger with a new one.
  8. Check the breather hose.
    A. Check that the breather hose is not damaged (kinked or clogged).
    B. Check whether the positive crankcase ventilation (PCV) valve is clogged.
    If the breather hose is bent or clogged, the internal pressure of the engine increases and engine oil is not supplied smoothly to the turbocharger. This may cause turbocharger damage and oil leakage. If the cause of the problem is found, replace the breather hose or related parts with new ones.
  9. Check the intake hose connected to the turbocharger.
    A. Check the intake hose for damage (kinks, crushing, disconnection, or tears).
    If the cross-section of the hose decreases because the air intake hose is bent or crushed, the air flow into the turbocharger decreases and the pressure before the turbocharger drops. This may cause turbocharger damage and oil leakage. If the air intake hose is disconnected or torn, foreign material enters the turbocharger and causes damage. If the air intake hose is damaged, replace it with a new one.
  10. Check the air cleaner.
    A. Check the air cleaner filter for contamination.
    B. Check the air cleaner filter for water intrusion.
    C. Check the air cleaner cover for contamination.
    D. Check whether the air cleaner filter is an genuine part.
    If the air cleaner filter is excessively wet or dirty, or a non-genuine part is used, the air intake into the turbocharger decreases and the pressure before the turbocharger drops. This may cause turbocharger damage and oil leakage. If the air cleaner filter is excessively wet or dirty, replace it with a new one.
    Replace the air cleaner filter according to the maintenance schedule.
  11. Check the intercooler hoses and pipes.
    A. Check that the charge air cooler hoses and pipes are connected correctly.
    B. Check the intercooler hoses and pipes for damage (kinks, disconnection, or tears).
    C. Check the intercooler hoses for damage such as cracks.
    D. Check that the clamps are in place.
    If the intercooler hoses and pipes are damaged or disconnected, oil may leak from the hoses and pipes, and the turbocharger may exceed its permissible speed, which may cause turbocharger damage. If the intercooler hoses and pipes are damaged, replace them with new ones.
    Use new clamps when replacing hoses and pipes.
  12. Inspect the intercooler.
    A. Check the intercooler pipes and tanks for damage (oil leakage or cracks).
    If the intercooler is damaged, the turbocharger may exceed its permissible speed, which may cause turbocharger damage. If the intercooler is damaged, replace it with a new one.
    When replacing the intercooler, use new clamps.
  13. Check the engine oil.
    A. Check the engine oil level.
    B. Check the engine oil for discoloration, water contamination, and loss of viscosity.
    C. Check the engine oil grade.
    If the engine oil level is low, the amount of engine oil supplied to the turbocharger decreases, and the bearings in the turbocharger may seize due to insufficient lubrication and cooling. If the cause of the problem is found, add or replace the engine oil.
    Replace the engine oil according to the maintenance schedule.
  14. Check the engine oil pressure.
    A. Engine oil pressure: Check the oil pressure using an oil pressure gauge after removing the oil pressure sensor from the cylinder block.
    B. Check the engine oil strainer in the oil pan if the engine oil level is low. Then check the nozzles for gas leakage if foreign material has accumulated on the oil strainer.
    If the engine oil level is low, the amount of engine oil supplied to the turbocharger decreases, and the bearings in the turbocharger may seize due to insufficient lubrication and cooling. If the cause of the problem is found, add or replace the engine oil. If foreign material has accumulated on the oil strainer, wash the oil filter and replace the nozzle washer with a new one after checking the nozzles for gas leakage. Inspect the engine oil-related parts, such as the oil pump, if necessary.
    Because the turbocharger rotates at high speed of 100,000 rpm or more, deterioration of the engine oil quality may damage the turbocharger bearings. Check the engine oil for discoloration, water contamination, viscosity deterioration, and reduced oil pressure.
  15. Check the injectors, sensors, EGR valve, etc. (Refer to Group FL).
    A. Check that the injectors operate correctly.
    B. Check the sensors, such as the Mass Air Flow Sensor (MAFS), Intake Air Temperature Sensor (IATS), and Boost Pressure Sensor (BPS), for proper operation.
    C. Check that the Exhaust Gas Recirculation (EGR) valve operates properly.
    If the injectors, sensors, exhaust gas recirculation (EGR) valve, etc. do not operate properly, engine power may be reduced. If the cause of the problem is found, replace the affected parts with new ones.
If no problem is found in the turbocharger, inspect the parts related to the turbocharger according to the following procedure.

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