Upper end engine noise

The fuel system, camshaft, timing drive components and valve train are common sources of upper end engine noise (ticking, knocking or rattle). Upper end engine noise can be determined using the EngineEAR/ChassisEAR or stethoscope on the valve cover bolts. If the noise is loudest from the valve cover bolts, then the noise is upper end. The EngineEAR/ChassisEAR or stethoscope can be used to further isolate the noise to the specific cylinder bank and cylinder. Removal of the valve covers will be required to pinpoint the source of the noise.

• Fuel System Noise
  • A common source of engine ticking noise is the switching of the fuel pressure control valve to fuel volume control valve. After the vehicle is started the high-pressure fuel injection pump switches modes and it makes a louder noise than when the vehicle was first started. There is an inherent ticking noise that comes from the high-pressure fuel injection pump as it switches to the more fuel efficient mode using fuel volume control valve only. This noise may be characteristic of the fuel system switching from the fuel pressure control valve to the fuel volume control valve. This noise may be more noticeable as the normal diesel engine noise diminishes. This is normal engine noise that can be verified by listening to another vehicle. If the noise is excessive or irregular, use the EngineEAR/ChassisEAR or stethoscope to isolate the noise.
• Valve Train
  • Hydraulic lash adjusters can make an engine ticking or tapping noise noticeable at any engine rpm or temperature and is audible through the wheel well or an open hood. However, with the hood down, hydraulic lash adjuster noise can be heard as a light tapping noise through the wheel well and is considered normal. The EngineEAR/ChassisEAR or stethoscope can be used to further isolate the noise to the specific cylinder bank and cylinder, some disassembly of the engine may be required to inspect for damage or wear.
• Turbocharger Noise
  • Some vehicles may exhibit a turbocharger spool-down (hoot) noise on engine throttle tip-out when engine oil temperature is below 65°C (150°F) and/or an oscillating turbocharger whine at idle with engine oil temperature below 10°C (50°F). The 6.7L diesel includes design improvements to reduce overall inherent diesel engine noise. These sound reduction improvements enable certain characteristic noises to be more easily heard. Using the incorrect engine oil can negatively impact the level of noise. For additional information, refer to Engine  for System Overview and Oil Requirements .