| Trouble Symptom 
 | Probable Cause 
 | Remedy 
 | 
| Engine misfire with abnormal internal lower engine noises. 
 | Worn crankshaft bearings. Loose or damaged engine drive plate.
 
 | Replace the crankshaft and bearings as required. Repair or replace the drive plate as required.
 
 | 
| Worn piston rings. (Oil consumption may or may not 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)
 
 | Repair or replace as required. 
 | 
| Excessively worn or mis-aligned timing chain. 
 | 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 cranking or other damage to the cylinder head and engine block cooling system | 
 | • | Coolant consumption may or may not 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, guides and/or valve stem oil seals. 
 | Repair or replace as required. 
 | 
| Worn piston rings. (Oil consumption may or may not cause the engine to misfire)
 
 | | • | Inspect the cylinder for a loss of compression. | 
 | • | Repair or replace as required. | 
 | 
| Engine noise on start-up that lasts only for a few seconds. 
 | Incorrect oil viscosity. 
 | | • | Use oil with the correct viscosity. | 
 | 
| | A brief and minor engine clatter sound immediately upon cold start may be considered normal. | 
 |  | 
| Upper 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, if applicable. 
 | Replace the timing chain tensioner as required. 
 | 
| Worn camshaft lobes. 
 | | • | Inspect the camshaft lobes. | 
 | • | Replace the timing camshaft and valve lifters as required. | 
 | 
| Worn valve guides or valve stems. 
 | Inspect the valves and valve guides, then repair 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, then repair as required. 
 | 
| Worn drive belt, idler, tensioner and bearing. 
 | Replace as required. 
 | 
| Lower engine noise, regardless of engine speed. 
 | Low oil pressure. 
 | Repair as required. 
 | 
| Loose or damaged drive plate. 
 | Repair or replace the drive plate. 
 | 
| Damaged oil pan, contacting the oil pump screen. 
 | | • | Inspect the oil pump screen. | 
 | • | Repair or replace as required. | 
 | 
| Oil pump screen loose, damaged or restricted. 
 | | • | Inspect the oil pump screen. | 
 | • | Repair or replace as required. | 
 | 
| Excessive piston-to-cylinder bore clearance. 
 | | • | Inspect the piston, piston pin and cylinder bore. | 
 | 
| Excessive piston pin-to-piston 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: 
 | • | The connecting rod bearings | 
 | • | The crankshaft pin journals | 
 | 
| Excessive crankshaft bearing clearance. 
 | Inspect the following components and repair as required: 
 | • | The crankshaft bearings | 
 | • | The crankshaft main journals | 
 | 
| Incorrect piston, piston pin and connecting rod installation 
 | | • | Verify the piston pins and connecting rods are installed correctly. | 
 | 
| 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: 
 | • | The connecting rod bearings | 
 | 
| Excessive crankshaft bearing clearance. 
 | Inspect the following components and repair as required: 
 | • | The crankshaft bearings | 
 | • | The crankshaft main journals | 
 | 
| Engine will not crank; crankshaft will not rotate. 
 | Hydraulically locked cylinder. 
 | • | Coolant/antifreeze in cylinder. | 
 | | 1) | Remove spark plugs and check for fluid. | 
 | 2) | Inspect for broken head gasket. | 
 | 3) | Inspect for cracked engine block or cylinder head. | 
 | 4) | Inspect for a sticking fuel injector and/or leaking fuel regulator. | 
 | 
| Broken timing chain and/or timing chain and/or timing chain gears. 
 | | 1) | Inspect timing chain and gears. | 
 | 
| Foreign materials in cylinder. 
 | • | Other foreign material | 
 | | 1) | Inspect cylinder for damaged components and/or foreign materials. | 
 | 2) | Repair or replace as required. | 
 | 
| Seized crankshaft or connecting rod bearings. 
 | | 1) | Inspect crankshaft and connecting rod bearing. | 
 | 
| Bent or broken connecting rod. 
 | | 1) | Inspect connecting rods. | 
 | 
| Broken crankshaft. 
 |  |