General engine diagnostics (Chevrolet Captiva 1)

STATE	Probable cause	Elimination
Difficult start (when starting the engine cold)	Fuel system malfunction
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	Not enough fuel in the fuel tank.	Fill the fuel tank with fuel.
	Clogged or dirty fuel filter.	Replace the fuel filter.
	Fuel line clogging.	Clean the fuel line.
	Fuel pump malfunction.	Replace the fuel pump.
	High pressure pump failure.	Replace the high pressure pump.
	Injector malfunction.	Replace the injectors.
	Water impurities or contamination in the fuel tank.	Clean the fuel tank.
	Compression pressure drop
	Insufficient tightening of the injector.	Tighten to the specified torque.
	Insufficient tightening of the glow plug.	Tighten to the specified torque.
	Cracked cylinder head gasket.	Tighten to the specified torque.
	Valve seat leak.	Replace the cylinder head.
	Valve stem failure.	Replace the valve.
	Insufficient elasticity or damage to the valve spring.	Replace the valve spring.
	Significant disruption in the operation of pistons and cylinders.	Replace piston rings.
	Severe wear of pistons, rings or cylinders.	Replace the cylinder block.
	Other
	Timing belt breakage.	Replace the timing belt.
	Positive crankcase ventilation (PCV) valve malfunction.	Check and replace PCV valve.
	Vacuum hose disconnected, damaged or leaking.	Establish a secure hose connection or replace it
	Leak in the intake system gasket.	Replace the intake system gasket.
Lack of engine power	Compression pressure drop	See page above.
	Fuel system malfunction
	Fuel line clogging.	Clean the fuel line.
	Clogged or dirty fuel filter	Replace the fuel filter
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	Other
	Clogged or dirty air filter element.	Clean or replace the air filter element.
	Leak in the intake system gasket.	Replace the intake system gasket.
	Weak brake performance.	Repair or replace brake mechanisms.
	Clutch slippage.	Adjust or replace the clutch.
Unstable idle speed.	Compression pressure drop	See page above.
	Fuel system malfunction
	Fuel line clogging.	Clean the fuel line.
	Clogged or dirty fuel filter	Replace the fuel filter
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	Fuel pump malfunction.	Replace the fuel pump.
	High pressure pump failure.	Replace the high pressure pump.
	Injector malfunction.	Replace the injectors.
	Other
	Clogged or dirty air filter element.	Clean or replace the air filter element.
	Positive crankcase ventilation (PCV) valve malfunction.	Check and replace PCV valve.
	Vacuum hose disconnected, damaged or leaking.	Establish a secure hose connection or replace it
	Leak in the intake system gasket.	Replace the intake system gasket.
"Slowness" of the engine (the engine does not respond immediately to pressing the gas pedal. This is especially noticeable when using cruise control or starting).	Compression pressure drop	See page above.
	Fuel system malfunction
	Fuel line clogging.	Clean the fuel line.
	Clogged or dirty fuel filter	Replace the fuel filter
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	Fuel pump malfunction.	Replace the fuel pump.
	Injector malfunction.	Replace the injectors.
	Other
	Clogged or dirty air filter element.	Clean or replace the air filter element.
	Leak in the intake system gasket.	Replace the intake system gasket.
Uneven engine running (engine power changes at a fixed speed and speed changes without changing the pressure on the gas pedal).	Compression pressure drop	See page above.
	Fuel system malfunction
	Fuel line clogging.	Clean the fuel line.
	Clogged or dirty fuel filter.	Replace the fuel filter.
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	Fuel pump malfunction.	Replace the fuel pump.
	High pressure pump failure.	Replace the high pressure pump.
	Injector malfunction.	Replace the injectors.
	Other
	Clogged or dirty air filter element.	Clean or replace the air filter element.
	Leak in the intake system gasket.	Replace the intake system gasket.
Increased detonation (within the throttle opening range, a metallic pop with a disturbed flash is heard).	Engine overheating	See "Overheating" in this section.
	Fuel system malfunction
	Clogged or dirty fuel filter.	Replace the fuel filter.
	Leak in the intake system gasket.	Replace the intake system gasket.
	Large carbon deposits due to combustion problems.	Remove carbon deposits.
Overheat	Cooling system malfunction
	Insufficient amount of coolant.	Add coolant.
	Thermostat malfunction.	Replace the thermostat.
	Cooling system fan malfunction.	Replace the cooling fan.
	Insufficient water pump supply.	Replace the water pump.
	The radiator is clogged or has a leak.	Clean and repair or replace the radiator.
	Lubrication system malfunction
	Low quality motor oil	Replace engine oil with the specified grade.
	Clogged oil filter or coarse filter.	Clean or replace the oil filter or coarse filter.
	Not enough engine oil.	Add engine oil.
	Decreased performance of the oil pump.	Replace or repair the oil pump.
	Engine oil leak.	Repair the associated component.
	Other
	Weak brake performance.	Repair or replace brake mechanisms.
	Clutch slippage.	Adjust or replace the clutch.
	Leak in the intake system gasket.	Replace the intake system gasket.
Insufficient fuel consumption.	Compression pressure drop	See page above.
	Fuel system malfunction
	Fuel line clogging.	Clean the fuel line.
	Clogged or dirty fuel filter	Replace the fuel filter
	Incorrect or contaminated fuel.	Clean the fuel and fuel line.
	High pressure pump failure.	Replace the high pressure pump.
	Injector malfunction.	Replace the injectors.
	Cooling system malfunction
	Thermostat malfunction.	Replace the thermostat.
	Other
	Incorrect installation of valves.	Repair or replace valves.
	Clutch slippage.	Repair or replace the clutch.
	Low tire pressure.	Bring the tire pressure to normal.
Increased engine oil consumption	Engine oil leak
	Loose attachment of the drain plug.	Tighten the drain plug.
	Loosened oil pan bolt attachment.	Tighten the oil pan bolt.
	Unsatisfactory condition of liquid gasket mastic.	Clean and apply liquid gasket mastic.
	Loose oil filter cover.	Tighten the oil filter cap.
	Loose oil pressure sensor connection.	Tighten the oil pressure sensor.
	Leakage in the front camshaft oil seal.	Replace the front camshaft oil seal.
	Leakage in the front crankshaft oil seal.	Replace the front crankshaft oil seal.
	Leakage in the rear crankshaft oil seal.	Replace the rear crankshaft oil seal.
	Cylinder head cover gasket leak.	Replace the cylinder head cover gasket.
	Cylinder head gasket leak.	Replace the cylinder head gasket.
	Mixing with oil in the combustion chamber.
	Piston ring sticking.	Remove carbon deposits and replace the ring.
	Piston or cylinder wear.	Replace the piston or cylinder block.
	Wear of piston ring or ring groove.	Replace piston or rings.
	The position of the cutting part of the piston ring is damaged.	Adjust the position.
	Abrasion or damage to the valve system.	Replace the valve system.
Low oil pressure	Lubrication system malfunction
	Incorrect oil viscosity.	Replace engine oil with the specified grade.
	Loosening of oil line pressure switch.	Tighten the switch.
	Not enough engine oil.	Add engine oil.
	Clogged coarse oil filter.	Clean the filter.
	Insufficient oil pump supply.	Replace the oil pump.
Engine noise	Valve noise
	Valve stem or guide wear.	Replace valve or cylinder head.
	The valve spring is weak.	Replace the valve spring.
	Wear of the valve tappet and bridge.	Replace the valve tappet or bridge.
	Noise from piston, ring, cylinder
	Wear of piston, ring or cylinder.	Replace piston, ring or cylinder block.
	Noise from connecting rod
	Connecting rod bearing wear.	Replace the connecting rod bearing.
	The connecting rod nut came loose.	Tighten the connecting rod nut to the specified torque.
	Crankshaft noise
	Main bearing wear.	Replace the main bearing
	Crankshaft journal wear.	Replace the crankshaft journal.
	Loose bearing cap bolts.	Tighten the bearing cap bolts to the specified torque.
	Increased clearance in the crankshaft thrust bearing.	Adjust or replace.
	Reduced oil pressure	See "Low Oil Pressure" in this section.