Engine coolant overheating signalled by the instrument / without visible vapour venting

Make: Alfa Romeo
Model: 147 Factory Service Manual
Year: 2000–2004
Section: Engine › Engine coolant overheating signalled by the instrument / without visible vapour venting

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Fault diagnosisEngine coolant overheating signalled by the instrument / without visible vapour venting

ENGINE COOLANT OVERHEATING SIGNALLED BY THE INSTRUMENT / WITHOUT VISIBLE VAPOUR VENTING

1.6 TS, 2.0 TS

0	PRELIMINARY NOTES	All OK	Problems met	Operation
		Results of the tests
	Temperature ijndication is managed by the engine control unit via a CAN line. Any faults in the electrical circuit and coolant temperature sensor are indicated by the system via activation of the engine control warning light and the indicator on the instrument panel pointing to zero.	Continue to Step 1
1	COOLANT LEVEL CHECK	All OK	Problems met	Operation
	Check the level of the coolant. Find out from the customer whether the problem has occurred previously Check the fluid consists of 100% PARAFLU Use a thermometer to check fluid temperature and compare it with the temperature displayed by the gauge	Continue to Step 2	Fluid too low and no traces of leaks noted	Restore fluid level
			100% PARAFLU	Dilute the PARAFLU 50%
			Temperature is true	Continue to Step 2
2	CHECK ON RADIATOR	All OK	Problems met	Operation
	Check the condition of the radiator. In particular, check for signs of deformation - traces of leaks - external dirt - fluid with excessive traces of rust.	Continue to Step 3	Radiator distorted	Replace the radiator Op. 1088B20
			Radiator dirty	Clean the radiator Op. 1088A20
			Radiator is leaking	Replace the radiator Op. 1088B20
			Liquid with excessive traces of rust	Clean the inside of the radiator and cooling circuit
3	THERMOSTAT OPERATION CHECK	All OK	Problems met	Operation
	Check that the thermostat is working properly	Continue to Step 4	Thermostat not working	Bleed the system as per standard procedure. Replace the thermostat if the problem persists
4	CHECKING FAN OPERATION	All OK	Problems met	Operation
	Test using an Examiner Activate the fan in active diagnosis mode If the fan works, ensure it comes on at the required temperature	Continue to Step 5	Fan not working	Activate the fan motor directly, replace if it does not work, check the following in order if it does work: specific fuses and relays on the engine bay control unit, condition of 1st speed resistor, specific wiring continuity and insulation. Check that the control unit activates the fan speed relays. If not, replace the i.e. control unit. If it does, replace the engine bay control unit
5	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	Fault persists

1.9 JTD 16V

0	PRELIMINARY CHECKS	All OK	Problems met	Operation
		Results of the tests
	Preliminarily check: the coolant level that there are no leaks that there is no engine oil in the expansion tank that the cooling radiator is not distorted or faulty that the radiator is not dirty / blocked	Continue to Step 1	Level not correct	Top up level
			Leaks detected	Move on to the step concerned
			Engine oil present	Replace the cylinder head gasket
			Radiator distorted	Reaplce the radiator
			Radiatoar dirty/blocked	Op. 1088A20
1	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket and check: that there are no control unit errors at the CAN	Continue to Step 2	There are errors in the control unit(s)	Carry out the specific test for the faulty control unit and continue following the instructions for the diagnostic equipment
2	CHECKING WITH DIAGNOSTIC EQUIPMENT	All OK	Problems met	Operation
	Keeping the diagnostic equipment (Examiner or other instruments) connected to the diagnostic socket: Carry out active diagnosis of fan Check the fan operating cycle	Continue to Step 5	Operation inconsistent	Continue to Step 3
3	ENGINE COOLING ELECTRICAL CIRCUIT CHECK	All OK	Problems met	Operation
	Check that the fan control/power line is working properly See E5020 ENGINE COOLING	Continue to Step 4	Connections not correct	Restore the connections See E5020 ENGINE COOLING
4	FAN OPERATION CHECK	All OK	Problems met	Operation
	Supply the fan directly and check its operation See E5020 ENGINE COOLING	Continue to Step 5	Fan not working	Replace the fan Op. 1088E10
5	COOLANT TEMPERATURE SENSOR CHECK	All OK	Problems met	Operation
	Check that the sensor is working properly.	Continue to Step 6	Sensor faulty	Replace sensor Op. 1056B50
6	THERMOSTAT OPERATION CHECK	All OK	Problems met	Operation
	Bleed the cooling system Check that the thermostat is working properly	Continue to Step 7	Thermostat not working	Replace the thermostat Op. 1088C30
7	CHECK ON WATER PUMP	All OK	Problems met	Operation
	Check that the water pump is working properly	Continue to Step 8	Pump faulty	Replace the pump Op. 1088C10
8	COOLING SYSTEM LEAKAGE CHECK	All OK	Problems met	Operation
	Carry out the cooling system leak test Op. 0510C30	Continue to Step 11	No seal with visible leaks	Eliminate the leaks
	Carry out the cooling system leak test Op. 0510C30	Continue to Step 11	No seal without visible leaks	Continue to Step 9
9	HEAD HYDRAULIC LEAKAGE TEST	All OK	Problems met	Operation
	Check the hydraulic seal of the cylinder headOp. 1016E04	Continue to Step 10	Seal ineffective	Renew the seal, if necessary replace the head
10	MONOBLOCK HYDRAULIC SEAL TEST	All OK	Problems met	Operation
	Check the hydraulic seal of the monobloc	Continue to Step 11	Seal ineffective	Renew the seal, if necessary replace the engine block
11	CHECK ON CORRECT OPERATION	All OK	Problems met	Operation
	Check that the fault is no longer present	End of diagnosis	The fault persists

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Parts & tools for this job For 2000 Alfa Romeo 147

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