Engine Noise on Start-Up, but Only Lasting a Few Seconds

Engine Mechanical - 3.0L LM2 Diesel | Diagnostic Information and Procedures | Document ID: 3318421

Cause	Correction
Incorrect oil filter without anti-drain back feature	Install the correct oil filter.
Incorrect oil viscosity	1. Drain the oil. 2. Install the correct viscosity oil.
High valve lash adjuster leak down rate	Replace the lash adjusters as required.
Worn crankshaft thrust bearing	1. Inspect the thrust bearing and crankshaft. 2. Repair or replace as required.
Damaged or faulty oil filter by-pass valve	1. Inspect the oil filter by-pass valve for proper operation. 2. Repair or replace as required.
Malfunctioning camshaft position actuators - improper oil viscosity or contamination. The result is camshaft actuator locking pin does not lock	1. Verify correct engine oil viscosity by changing the engine oil and filter. Reevaluate the concern. 2. Isolate the noise to a specific camshaft position actuator. 3. Replace the camshaft actuator, oil and filter.
Excessive piston-to-cylinder bore clearance	1. Inspect the piston and piston skirt, connecting rod, and cylinder bore. 2. Repair or replace all damaged components.