Radiator fans kicking in too late?

[pcspinheiro]

Dear all,

I have an issue with my 2002 Xsara Estate (2.0i 16V, 136 HP, about 165.000 Km) that I already witnessed last September when I first bought it, but hasn't bothered me much due to the very cold weather here in Denmark. In warmer weather, an essentially in city traffic, the engine will heat up to over 100ºC (more like 110ºC) before the radiator fans kick in. When that happens I get a sudden stutter from the engine (maybe from the large power draw?) and the orange check engine light comes on, together with an "anti pollution fault" warning on the multifunction display. The engine will then cool down to about 90ºC but will keep on climbing up and down if in slow traffic. When left off for over a couple of hours the fault will no longer display.

What could be wrong here? It appears that in my particular version there is only one coolant temperature sensor but is there a sensor solely responsible for the fans that could need replacing?

Any hints as to what to look for are much appreciated. I will be doing an oil change, coolant renewal and other small interventions soon and would like to get it all done in one go.

Best wishes,

Paulo.

[Mandrake]

Do you have air conditioning ? If so do the fans come on at the slow speed when you turn the A/C on ? I'm guessing not.

It sounds like the slow fan speed is not working (which should come on around 97 degrees) and its heating up until it gets to the threshold for the high fan speed which is approximately 105-110 degrees.

If your fan goes straight to the high speed from stationary that could easily cause the engine to stutter and nearly stall from the load as normally it would never go from stopped directly to full fan speed, it would go from already spinning at the slow speed to full speed which is less of a surge in load on the alternator.

On a Xantia the problem is usually with a faulty fan or relay - the fans are switched in series for low speed and parallel for high speed. If one fan goes open circuit neither will work on the slow speed, and only the functioning fan will work on the high speed. When your fan(s) do come on are they both spinning or just one ?

Hopefully someone with direct experience of a Xsara will come along and confirm whether they use the same general fan control system as a Xantia...

[pcspinheiro]

Those are very nice hints you gave me! No, the fans do not turn at low speed when the air con is switched on. I have to check if they both run at high speed when the car stutters and the anti pollution fault comes on. If only one runs can that one be replaced individually? If both run does that mean a relay or an ECU fault?

Thanks again,

Paulo.

[pcspinheiro]

Just forgot, I guess I can easily test the fans by directly connecting them to the battery?

[Lighty]

On the Xsara the two fan control resistors are in the fan housing. If you take off the front upper grille , you will see all the wires leading to two multi plugs, these are the resistors, held in by 1 torx screw each normally.

[pcspinheiro]

Just an update on my issue, I have finally found the time to look into it and it turns out that the low speed control relay is ruined; the metal coil is broken and the circuit could never work. Just ordered a new one and should be here in a couple of days. That should fix it, thanks for the help again!

By the way, my car only has one large fan, not 2 as I was led to believe from some posts.

[pcspinheiro]

Just to let you know, issue solved with the new relay. Thank you all for your help!

Now on to find other issues!
Paulo.