Radiator Cooling Fan

[JBSpain]

The cooling fan on my wife’s C3 has developed a fault and apparently does not function all the time. I have yet to experience the fault on the odd time I drive the car.

 

What apparently happens is the dashboard when the engine is running at normal temperature displays 3 yellow/orange bars but on the odd occasion it shoots to the top with all bars on yellow/orange and the top one on red – meaning something is wrong!

 

On various occasions (not at the time of the fault) I have lifted the bonnet and observed the car and the fan seems to cut in and out as normal and I can’t get the problem to repeat itself.

 

Citroen say it must be the cooling fan at fault and want to replace. Admittedly they say it is not normal for the fan to fail but recognise my C3 has developed more faults than most C3s! What’s irionic is the fan failed on it’s first trip out after spending 2 weeks in the citroen garage but they say there were not doing any work on anything that would impact on the fan.

 

Just wondering if anyone else has experienced this problem and if anyone has tests that could be performed to confirm it definitely is the cooling fan.

 

Already tried re-setting ECU by disconnecting battery as that seems to be the first recommendation for any type of electrical fault but problem did repeat itself after that again.

 

The fan has two plugs one with 2 heavier type wires and the other with 3 lighter type wires. It would seem the plug 2 two wires is the power feed and the plug with the 3 wire probably running off to sensor/ECU but I’m no auto electrician.

 

All comments/suggestions as always greatly appreciated.

[paul.h]

What year, model is your car ?

 

This has happened twice now to our car 2003 1.4sx petrol. Both on the same journey and same day of the year on 25/12/2007 and 2009 on the way from Warrington to Leeds with temperatures about freezing. First time at the very end of the journey the temp went to max and the fan came on. I did lots of checks but found nothing but bought a new thermostat and temperature sensor but did not fit them since the fault did not recur. Second time I was still on the M62 motorway on the hilly bits but rather than stop (after the previous experience) I put the cabin heater and fan on full and opened the driver's window and slowed to between 50 to 60 mph for the last 20 miles. This managed to control the temperature and reduce the number of orange bars - this also indicated the high temperature switch (which is additional to the temperature sensor) had not caused the gauge to go to max.

 

Using a code reader with live data, 2 bars starts about 70°C, 3 bars covers from about 78 to at least 96°C, it did not go higher in the test so I need to do more tests. I suspect either the sensor or the thermostat may need replacing - most likely the thermostat is not opening fully although with other cars faulty thermostats have always opened too soon so the engine has been cold.

 

Following may be of use from the RTA French manual and Haynes manual

- thermostat starts to open at 89°C and full open at 101°C.

- high temperature switch set at 118°C. Single wire sensor, putting the connector to earth may start the fan and give full scale on the bars.

- radiator fan has 2 speeds depending on engine temperature and air con.

- the expansion tank cap pressure is 1.4 barg equivalent to 126°C steam if the coolant is boiling.

- the temperature sensor resistance varies with temperature. 2 wire sensor, bridging the connector wires may start the fan and give full scale on the bars.

3800 ohms = 10°C

2500 = 20

800 = 50

230 = 90

 

Things that I still want to check include

- sensor fault

- thermostat not opening fully

- radiator blocked internally or externally

- water pump fault

- anti freeze needs replacing

- fan not running - although I would think it is not needed at 70 mph on the motorway

- poor air flow through the radiator

- coolant level although it is always ok in the tank

- air in the cylinder head but by now I think it would have been ok or the head may have damaged

- temperatures when everything happens - bars/fan starts/thermostat opens

[JBSpain]

Hi Paul

 

Thank you for your detailed reply. It's certainly given me something to go on.

 

The car in questions is:-

 

C3 1.4i CAS SX PLUS AUTO

Year: 2003

 

As I live on the coast in the south of Spain I can rule out anything to do with freezing conditions!

 

Any idea where the thermostat and sensor are situated or how to identify them etc?

[paul.h]

If you follow the radiator top hose back to the cylinder head, the thermostat is the black plastic housing at the end of the hose. It is not a separate thermostat inside the housing but is built into the housing itself.

 

The temperature sensor (2 wire connector) is on top of the cylinder head next to the housing. There is also a separate high temperature switch (single wire connector) which is on the side of the cylinder head below the thermostat housing.

[paul.h]

- high temperature switch set at 118°C. Single wire sensor, putting the connector to earth may start the fan and give full scale on the bars.

- the temperature sensor resistance varies with temperature. 2 wire sensor, bridging the connector wires may start the fan and give full scale on the bars.

 

Whilst I had the air filter box removed (to clean the throttle body) I did these 2 checks with the ignition on but not far enough to start the engine (2003 1.4sx petrol).

- earthing the blue, single wire connector put the temp gauge to full but did not start the fan - maybe I would need to run the engine for this but did not want to try with the filter off.

- bridging the green 2 wire connector put the temp gauge to full, again did not start the fan, but also brought up a fault code P0117 - temp sensor earth fault, which I had to clear with a Citroen specific reader (Sealey one worked) since on OBDII setting it did not see the code. So the system is sensible enough to realise there should be some resistance but I would not recommend doing this test without a code reader to erase the fault code that will come up..

 

Additionally the temp sensor resistance measured 3600 ohms but the reader gave 30°C and not the values in the RTA manual.

[Guest pazauk]

Did you get your fan working again? As I have a similar problem with my 1.4hdi 16v when I turn on the air con the clutch on the compressor kicks in the radiator fan start then 20 seconds later the air con cuts out and the temp gauge on the dash max’s out. I have to turn the engine of and start the car again and its all back to normal

[paul.h]

If the temperature gauge goes to max I think the air con is automatically switched off.