T-series engine cooling fan inoperative

[Pencil Tip]

I have noticed that my cooling fan is not operating when it should. I was sat idling at temporary traffic lights and noticed that the temperature gauge was above normal.

Is the sensor on the engine or is it the little one on the side of the radiator? Could it be a bad relay? If so, where is it located?

The fan actually works using an external power source.

[Julesmat50]

Are you sure that isn't normal? Admittedly mine is a diesel, but my cooling fan doesn't cut in until the gauge reaches somewhere around 2/3 - 3/4 of max, so quite a way above the halfway point. If that ISN'T normal for you i.e. the fan has always cut in at a different point, but now doesn't and the fan works when operated outside, then suspect the coolant temp sensor for the fan, which I believe is the one in the radiator.

[220 GSi turbo]

According to the Rover electrical manual, the normally aspirated and non-aircon T-series uses the same fan circuit as the 1.4 and diesel versions. (The turbo versions and cars equipped with aircon have a much more complex circuit controlled via the MEMS ECU).

Annoyingly, it doesn't mention the location of the sensor ("low temperature switch"), but it has two wires connected to it: light green with grey stripe and grey with blue stripe. The sensor circuit is fed from 15 Amp fuse no.15 in the dashboard fusebox.

The motor is fed from 20 Amp fuse no.4 in the engine bay fusebox, via a relay mounted in the same place which is triggered by the sensor mentioned above.

Hope that helps.....

[Pencil Tip]

Thanks for your help guys.

[Pencil Tip]

Okay. Both fuses are good, as is the relay. I disconnected and shorted out the radiator sensor wiring to fool the ECU into thinking the sensor has gone closed circuit, i.e. an over-temperature engine situation and the fan does work.

So, perhaps I can conclude that the radiator sensor is bad.

Does the coolant leak out if I remove the sensor? Perhaps a daft question, but just wanted to be sure.

[RoverRevival]

The t-series has a 2 stage fan. low/high but also (on a nasp) the second fan is mainly only used for the air con.

Don't know if that helps.

[Pencil Tip]

Thanks for the info.

Yes, mine has a second smaller fan in front of the a/c condensor. What does the 2 stage fan actually do? Mine has only cycled on and off during prolonged engine idling.

[RoverRevival]

basically, if the first speed is not enough to keep consistent or lower the temp, or the temp rises too quickly it will spin faster

[Pencil Tip]

Ah, no mine just has one fast speed.