Engine Noise Under Load
| Cause | Correction |
|---|---|
| Low oil pressure | Insufficient or poor oil supply to components. Perform oil pressure test. Repair or replace all damaged components. |
| Loose torque converter bolts | Inspect the torque converter bolts and flywheel. Repair or replace all damaged components. |
| Loose and/or damaged flywheel | Inspect the flywheel and flywheel attaching bolts. Repair or replace all damaged components. |
| Excessive piston-to-cylinder bore clearance | Inspect the piston rings for low ring tension, broken or worn rings, inspect cylinder bore. Repair or replace all damaged components. |
| Excessive crankshaft thrust bearing clearance | Inspect the crankshaft end play and crankshaft thrust bearings. Repair or replace all damaged components. |
| Excessive crankshaft bearing clearance | Inspect the crankshaft bearings and crankshaft journals. Repair or replace all damaged components. |
Engine Noise Under Load
Engine Noise on Start-Up, but Only Lasting a Few Seconds
| Cause | Correction |
|---|---|
| Incorrect oil filter without anti-drainback feature | Install the correct oil filter. |
| Incorrect oil viscosity | Drain the engine oil and replace with the correct viscosity oil. |
| High stationary hydraulic lash adjuster (SHLA), valve lifter, leak down rate | Replace the SHLAs, valve lifters, as required. |
| Worn crankshaft thrust bearing | Inspect the thrust bearing and crankshaft. Repair or replace as required. |
| Damaged or faulty oil filter by-pass valve | Inspect the oil filter by-pass valve for proper operation. Repair or replace as required. |
Engine Noise on Start-Up, but Only Lasting a Few Seconds
Base Engine Misfire with Abnormal Valve Train Noise
| Condition | Action |
|---|---|
| Loose, worn or damaged valve bridge and finger-follower | Inspect valve bridge and finger-follower. Repair or replace all damaged components. |
| Broken valve springs | Inspect valve springs. Repair or replace all damaged components. |
| Sticking valve | Carbon on the valve stem or valve seat may cause the valve to stick. Inspect valves and valve guides. Repair or replace all damaged components. |
| Worn or faulty camshaft lobes | Inspect camshaft lobes. Repair or replace all damaged components. |
Base Engine Misfire with Abnormal Valve Train Noise
Upper Engine Noise, Regardless of Engine Speed
| Condition | Action |
|---|---|
| Low oil pressure | Insufficient or poor oil supply to valve train. Perform oil pressure test. Repair or replace all damaged components. |
| Improper lubrication to the valve finger-follower | Inspect valve finger-follower, valve bridge, valve finger follower lifter, oil pump and engine block oil galleries. Repair or replace all damaged components. |
| Worn or damaged valve finger-follower | Inspect valve bridge and finger-follower. Repair or replace all damaged components. |
| Sticking valve | Carbon on the valve stem or valve seat may cause the valve to stick. Inspect valves and valve guides. Repair or replace all damaged components. |
| Worn or faulty camshaft lobes | Inspect camshaft lobes. If damaged replace camshaft and all valve finger-followers. |
| Damaged or misaligned timing gears | Inspect timing gears. Replace all damaged components. |
Upper Engine Noise, Regardless of Engine Speed
Lower Engine Noise, Regardless of Engine Speed
| Condition | Action |
|---|---|
| Worn accessory drive components (abnormalities such as severe cracking, bumps or missing areas in the accessory drive belt and/or misalignment of the system components.) | Inspect the accessory drive components. Repair or replace all damaged components. |
| Low oil pressure | Insufficient or poor oil supply to crankshaft and connecting rod bearings. Perform oil pressure test. Repair or replace all damaged components. |
| Leaking and/or sticking fuel injection nozzle (A stuck fuel injection nozzle can cause a noise similar to a damaged piston, rod or rod bearing.) | Inspect the cylinder balance with scan tool to help locate the cylinder that is the source of the noise. If you cannot locate the cylinder that is the source of the noise, diagnose the engine for mechanical damage. If it has been determined that the fuel injection nozzle is causing the noise, replace the fuel injection nozzle. |
| Loose and/or damaged crankshaft pulley | Inspect crankshaft pulley and pulley bolt. Repair or replace all damaged components. |
| Loose torque converter bolts | Inspect torque converter bolts and flywheel. Repair or replace all damaged components. |
| Loose and/or damaged flywheel | Inspect flywheel and flyweel attaching bolts. Repair or replace all damaged components. |
| Excessive piston pin-to-bore clearance | Inspect the piston, piston pin, and the connecting rod. Repair or replace all damaged components. |
| Misaligned or bent connecting rod | Inspect connecting rod and connecting rod bearings. Repair or replace all damaged components. |
| Excessive connecting rod bearing clearance | Inspect the connecting rod bearings, connecting rods, crankshaft and crankshaft journals. Repair or replace all damaged components. |
| Excessive crankshaft bearing clearance | Inspect the crankshaft bearings and crankshaft journals. Repair or replace all damaged components. |
Lower Engine Noise, Regardless of Engine Speed