Symptom | Probable cause | Remedy |
Knocking of crankshaft and bearing | Worn main bearing Seized bearing Bent crankshaft Excessive crankshaft end play | Replace Replace Replace Replace thrust bearing |
Piston and connecting rod knock | Worn bearing Seized bearing Worn piston pin Worn piston in cylinder Broken piston ring Improper connecting rod alignment | Replace Replace Replace piston and pin or connecting rod Recondition cylinder Repair or replace Replace |
Noisy valves | Faulty auto-lash adjuster Thin or diluted engine oil (low oil pressure) Worn or damaged valve stem or valve guide | Replace Change Replace |
Excessively worn cylinder and piston | Shortage of engine oil Dirty engine oil Poor quality of engine oil Improperly assembled piston and connecting rod Improper piston ring end clearance Dirty air cleaner | Add or replace Check oil level on daily basis Replace Use proper oil Repair or replace Replace Clean air cleaner assembly and replace the air filter |
Connecting rod and main beaing noise | Insufficient oil supply Thin or diluted engine oil Excessive bearing clearance | Check engine oil level Change and determine cause Replace |
Damaged crankshaft bearing | Shortage of engine oil Low oil pressure Poor quality of engine oil Worn or out-of -round of crankshaft journal Restricted oil passage in crankshaft Worn bearing Bearing improperly installed Non-concentric crankshaft or bearing | Add or replace Check oil level on daily basis Adjust or repair Use proper engine oil Replace Clean Replace bearing and check engine oil and lubrication system Replace Replace |
Timing belt noise | Incorrect belt tension | Replace |
Low compression | Blown cylinder head gasket Worn or damaged piston rings Worn piston or cylinder Worn or damaged valve seat | Replace gasket Replace rings Repair or replace piston and/or cylinder block Repair or replace valve and/or seat ring |
Oil pressure drop | Low engine oil level Faulty oil pressure switch Clogged oil filter Worn oil pump gears or cover Thin or diluted engine oil Oil relief valve stuck (open) Excessive bearing clearance | Check engine oil level Replace Replace Replace Change and determine cause Repair Replace |
High oil pressure | Oil relief valve stuck (closed) | Repair |
Excessive engine rolling and vibration | Loose engine roll stopper (front, rear) Loose transaxle mount bracket Loose engine mount bracket Loose center member Broken transaxle mount insulator Broken engine mount insulator Broken engine roll stopper insulator | Re-tighten Re-tighten Re-tighten Re-tighten Replace Replace Replace |
Low coolant level | Leakage of coolant Damaged radiator core joint Corroded or cracked hoses (Radiator hose, heater hose, etc) Faulty radiator cap valve or setting of spring Faulty thermostat Faulty engine coolant pump | Replace Replace Replace Replace Replace |
Clogged radiator | Foreign material in coolant | Replace |
Abnormally high coolant temperature | Faulty thermostat Faulty radiator cap Restriction of flow in cooling system Loose or missing drive belt Faulty engine coolant pump Faulty temperature gauge or wiring Faulty electric fan Faulty thermo-sensor on radiator Insufficient coolant | Replace parts Replace Replace Adjust or replace Replace Repair or replace Repair or replace Replace Refill coolant |
Abnormally low coolant temperature | Faulty thermostat Faulty temperature gauge or wiring | Replace Repair or replace |
Leakage from oil cooling system | Loose hose and pipe connection Blocked or collapsed hose and pipe | Replace Repair or replace |
Inoperative electrical cooling fan | Damaged | Replace or repair |
Exhaust gas leakage | Loose connections Broken pipe or muffler | Re-tighten Repair or replace |
Abnormal noise | Detached baffle plate in muffler Broken rubber hanger Pipe or muffler contacting vehicle body Broken pipe or muffler | Replace Replace Correct Repair or replace |
