Troubleshooting

Symptom	Possible Cause	Remedy
Low compression	Cylinder head gasket leak; Worn or damaged piston rings; Worn piston or cylinder; Worn or damaged valve seats	Replace gasket; Replace rings; Repair or replace pistons and/or cylinder block; Repair or replace valves and/or valve seats
Low oil pressure	Low oil level in oil pan; Faulty oil pressure switch; Clogged oil filter; Worn oil pump gears or cover; Low engine oil viscosity (dilution or thinning); Pressure relief valve stuck open; Excessive bearing clearance	Check oil level; Replace; Replace; Replace; Replace; Replace oil and find cause of malfunction; Repair; Replace
Excessive engine vibration	Loose engine front and rear mount brackets; Loose transmission mount bracket; Loose engine side mount bracket; Loose subframe crossmember; Faulty transmission mount; Faulty engine side mount; Faulty engine front or rear mount	Tighten; Tighten; Tighten; Tighten; Replace; Replace; Replace
Valve noise	Low engine oil viscosity (dilution or thinning) or low oil pressure; Worn or damaged valve stem or valve guide; Excessive valve clearance	Replace oil; Replace; Adjust valve clearance
Connecting rod or crankshaft main bearing noise	Insufficient oil flow to bearings; Low engine oil viscosity (dilution or thinning); Excessive bearing clearance	Check engine oil level; Replace oil and find cause of malfunction; Replace
Timing belt noise	Incorrect belt tension	Adjust belt tension
Low coolant level	Coolant leaks: 1. Radiator or heater hoses 2. Faulty radiator cap 3. Thermostat housing 4. Radiator 5. Water pump	Repair or replace parts; Install correctly or replace; Replace gasket or housing; Replace or repair; Replace parts
Radiator clogged	Foreign matter in coolant	Replace coolant
Abnormally high coolant temperature	Faulty thermostat; Faulty radiator cap; Restricted coolant flow in cooling system; Loose or broken generator drive belt; Faulty water pump; Faulty coolant temperature sensor or wiring; Faulty radiator electric fan; Low coolant level	Replace parts; Replace parts; Clean cooling system or replace parts; Adjust tension or replace; Replace; Repair or replace; Repair or replace; Add coolant
Abnormally low coolant temperature	Thermostat malfunction. Engine coolant temperature sensor or its wiring malfunction	Replace. Repair or replace
Radiator cooling fan does not operate	Malfunction of: engine coolant temperature sensor, radiator cooling fan motor, radiator cooling fan motor relay, wiring or fuse	Repair or replace
Exhaust system leakage	Loose connection joints. Defective exhaust pipe or muffler	Tighten. Replace or repair
Abnormal noise from exhaust system	Burnt-through baffles in muffler. Defective rubber-metal hanger bracket. Exhaust pipe or muffler contacts body. Defective exhaust pipe or muffler	Replace. Replace. Correct. Repair or replace

Troubleshooting

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