Engine misfire with abnormal internal lower engine noises

Loose or improperly installed engine flywheel

Repair or replace the flywheel as required.

Worn piston rings

(Oil consumption may cause the engine to misfire.)

Inspect the cylinder for a loss of compression.

Repair or replace as required.

Worn crankshaft thrust bearings.

Replace the crankshaft and bearings as required.

Engine misfire with abnormal valve train noise

Stuck valves

(Carbon buildup on the valve stem can cause the valve not to close properly.)

Repair or replace as required.

Excessive worn or mis-aligned timing chain

Inspect the timing chain alignment.

Reinstall the timing chain as required.

Replace the timing chain and sprocket as required.

Worn camshaft lobes

Replace the camshaft and valve lifters.

Engine misfire with coolant consumption

• Faulty cylinder head gasket and/or cracking or other damage to the cylinder head and engine block cooling system

• Coolant consumption may cause the engine to overheat.

Inspect the cylinder head and engine block for damage to the coolant passages and/or a faulty head gasket.

Repair or replace as required.

Engine misfire with excessive oil consumption

Worn valves, valve guides and/or valve stem oil seals

Repair or replace as required.

Worn piston rings

(Oil consumption may cause the engine to misfire.)

Inspect the cylinder for a loss of compression.

Repair or replace as required.

Engine noise on start-up, but only lasting a few seconds.

Incorrect engine oil viscosity

Drain the engine oil.

Refill with the correct viscosity engine oil.

Worn crankshaft thrust bearing

Inspect the thrust bearing and crankshaft.

Repair or replace as required.

High engine noise regardless of engine speed

Low oil pressure

Repair or replace as required.

Broken valve spring

Replace the valve spring.

Worn or dirty valve lifters.

Replace the valve lifters.

Stretched or broken timing chain and/or damaged sprocket teeth.

Replace the timing chain and sprockets.

Worn timing chain tensioner

Replace the timing chain tensioner as required.

Worn camshaft lobes

Inspect the camshaft lobes.

Replace the camshaft and/or valve lifters as required.

Worn valve guides or valve stems

Inspect the valves and valve guides

Replace the valve and/or cylinder head as required.

Stuck valves

(Carbon on the valve stem or valve seat may cause the valve to stay open.)

Inspect the valves and valve guides

Repair and replace the valve and/or cylinder head as required.

Low engine noise regardless of engine speed

Low oil pressure

Repair or replace damaged components as required.

Loose or damaged flywheel

Repair or replace the flywheel.

Damaged contact area between oil pan and the oil pump screen

Inspect the oil pan.

Inspect the oil pump screen.

Repair or replace as required.

Loose, damaged or restricted oil pump screen 

Inspect the oil pump screen.

Repair or replace as required.

Excessive piston-to-cylinder bore clearance

Inspect the piston and cylinder bore.

Repair as required.

Excessive piston pin-to-bore clearance

Inspect the piston, piston pin and the connecting rod.

Repair or replace as required.

Excessive connecting rod bearing clearance.

Inspect the following components and repair as required.

• Connecting rod bearings

• Connecting rods

• Crankshaft

• Crankshaft journals

Excessive crankshaft bearing clearance

Inspect the following components and repair as required.

• Crankshaft bearings

• Crankshaft journals

Incorrect piston, piston pin and connecting rod installation

Verify the piston pins and connecting rods are installed correctly.

Repair as required.

Engine noise under load

Low oil pressure

Repair or replace as required.

Excessive connecting rod bearing clearance

Inspect the following components and repair as required.

• Connecting rod bearings

• Connecting rods

• Crankshaft

Excessive crankshaft bearing clearance

Inspect the following components and repair as required.

• Crankshaft bearings

• Crankshaft journals

• Cylinder block crankshaft bearing bore

Engine will not crank.

(Crankshaft will not rotate.)

Hydraulically locked cylinder

• Coolant/antifreeze in cylinder

• Oil in cylinder

• Fuel in cylinder

Remove injectors and check for fluid.

Inspect for broken head gasket.

Inspect for cracked engine block or cylinder head.

Inspect for a sticking fuel injector and/or leaking fuel regulator.

Broken timing chain and/or timing chain sprocket

Inspect timing chain and sprocket.

Repair as required.

Foreign material in cylinder

• Broken valve

• Piston material

• Foreign material

Inspect cylinder for damaged components and/or foreign materials.

Repair or replace as required.

Seized crankshaft or connecting rod bearings

Inspect crankshaft and connecting rod bearing.

Repair or replace as required.

Bent or broken connecting rod

Repair or replace as required.

Inspect connecting rods.

Broken crankshaft

Inspect crankshaft.

Repair or replace as required.