Citroen C3 2002 1.4 petrol overheating (or not?)

[ozvtr]

Let's say it is in the third light and all of the sudden in a red light it goes to the top and the car fan opens at full speed for 2 minutes, then the temperature goes back to 3, fan turns off and everything is normal again.

Are you saying that the radiator fan actually runs when you get all the temp lights on? WHILE YOU ARE JUST DRIVING THE CAR AROUND? How do you know the radiator fan is running?

If your problem is a sensor then the fan will run, but the engine won't overheat.

If your problem is the fan, then the fan won't run but the engine WILL overheat.

One explains the engine boiling over but the other doesn't. Do you have two faults at the same time????

Why do I get all the hard ones?

Disconnect the blue sensor...you have absolutely nothing to lose! You can also replace the green sensor if you want, they are not that expensive and not hard to replace. If the problem still persists...you know what it's going to be.

[kyrpousin]

Yes, I have auto a/c

Ok, in that case I'm now very suspicious of the radiator fan.
As I said, the fan has a built-in electronic controller that will vary the fan speed from off to full speed. The built-in controller also provides feed back to the engine ECU about the status of the fan. A fault in the fan will cause all the temp lights to come on and issue three warning beeps. Just like a sensor failure.
Only the cars with auto A/C have this type of radiator fan! Which is why I needed to know.
Again, the electronics in these things tend to be intermittent, and so tend to work sometime and then not others. Which is why it passed the test earlier.
But more importantly, it also answers the question as to why the engine boiled over.
To confirm this, the next time all the lights come on, and you hear the three beeps, pull over BUT DO NOT STOP THE ENGINE, open the bonnet and see if the fan is running.
WITH ALL THE TEMP LIGHTS ON THE FAN MUST BE RUNNING (under any circumstance)!!! If not, that's a failure of the fan!
Even with a failure of the green or blue sensors, the fan should still come on!
If the fan is not working with the car at low speeds (or stopped), the engine will boil over! If you manage to keep the car moving, that will cool the radiator, and you have less of a chance of the engine boiling over.

Most of the time when the temperature rises the fan opens but don't know if it opens other times. Also you said about the fan controller being expensive, how expensive is it and is only the controller replaced or the whole fan?

[ozvtr]

Also you said about the fan controller being expensive, how expensive is it and is only the controller replaced or the whole fan?

You can only buy the whole fan assembly.
This is just an example from EBay >click here< I don't know what price they would be in your country.
The part numbers are 1253.C6 , 1253.H3 and 696133

[kyrpousin]

Also you said about the fan controller being expensive, how expensive is it and is only the controller replaced or the whole fan?

You can only buy the whole fan assembly.
This is just an example from EBay >click here< I don't know what price they would be in your country.
The part numbers are 1253.C6 , 1253.H3 and 696133

Thanks for all your help. These are actually like my car fan, with the two cable connectors on the upper side, unlike the fans that car part sites say that my car needs.
However, are all those 3 fan part numbers do the same job and as good as they are supposed to? In what place of the old fan is the part number written?

[ozvtr]

Typically, the different part numbers could mean one is superseded. So, one might be a new part number and one might be an old part number. Sometimes it just means that they come from different manufacturers.
They will all do the same job but you might not have a choice as to which one you can find!
Remember, the advertised fan on EBay is aftermarket and not genuine. In this case the manufacturer of that fan says their product will replace those part numbers.
If you were to go to Citroen for a genuine fan they would sell you whatever their parts list says. It doesn't mean it's better or worse, just that's what they have in stock.