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Home >> Cadillac >> 2013 >> Escalade Base, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 15 (Engine Mechanical - Hybrid (LZ1) - Diagnostic Information And Procedures) >> Diagnostic Information and Procedures >> Upper Engine Noise, Regardless of Engine Speed

Upper Engine Noise, Regardless of Engine Speed

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Upper Engine Noise, Regardless of Engine Speed

Cause Correction
Review the system operation in order to familiarize yourself with the system functions. As required, disable the auto-stop function prior to repair. Refer to Hybrid Modes of Operation Description .
Low oil pressure
  1. Perform an oil pressure test. Refer to Oil Pressure Diagnosis and Testing .
  2. Repair or replace components, as required.
Loose and/or worn valve rocker arm attachments
  1. Inspect the valve rocker arm, bolt, and pedestal.
  2. Repair or replace, as required.
Worn or damaged valve rocker arm
  1. Inspect the rocker arm for wear or missing needle bearings
  2. Replace the valve rocker arms, as required.
Bent or damaged push rod Inspect the following components and replace, as required:
  • The valve rocker arm
  • The valve push rod
  • The valve lifter
  • The valve lifter guide
  • The piston

Inspect the top of the pistons for valve contact. If the top of the piston shows valve contact, replace the piston and pin assembly.
Improper lubrication to the valve rocker arms Inspect the following components and repair or replace, as required:
  • The valve rocker arm
  • The valve push rod
  • The valve lifter
  • The oil filter bypass valve

    The valve is now internal to the oil filter.

  • The oil pump and pump screen
  • Restrictions within the engine block oil galleries
Broken valve spring Replace the valve spring and spring shim.
Worn or dirty valve lifters Replace the valve lifters, as required.
Active fuel management valve lifter with a broken spring Replace the valve lifters, as required.
Improper operation of the active fuel management oil pressure relief valve Repair, as required. Refer to Cylinder Deactivation (Active Fuel Management) Oil Pressure Relief Valve Diagnosis and Testing .
Improper operation of the camshaft position (CMP) actuator and/or control system Repair, as required. Refer to Camshaft Position Actuator and Solenoid Valve Diagnosis and Testing .
Stretched or broken timing chain and/or damaged sprocket teeth Replace the timing chain, tensioner, sprocket, and camshaft position actuator.
Worn engine camshaft lobes
  1. Inspect the engine camshaft lobes.
  2. Replace the camshaft and valve lifters, as required.
Worn valve guides or valve stems Inspect the following components and repair, as required:
  • The valves
  • The valve guides
Stuck valves
Carbon on the valve stem or valve seat may cause the valve to stay open.
Inspect the following components and repair, as required:
  • The valves
  • The valve guides
Cut or damaged oil pump screen O-ring seal which may cause aeration of the engine oil Repair, as required. Refer to Oil Pressure Diagnosis and Testing .