2001 1.8 Engine cooling fans - miegas
Hi guys,
Does anyone know when and how often should the engine cooling fans turn on?They should cut in when the engine reaches some temperature.What temperature is it?Temperature indicator is always standing in the middle position (when I start the engine the indicator is in the initial state, but when I drive a few hundred meters, it gets in the middle and keeps standing in that position all the time). As you know there are two fans on the radiator, I guess one is for air conditioning and the other one for cooling the engine.Am I right?Because when I turn A/C, one fan is cutting in and working, but not the other one.So I suspect that there is something wrong with the second fan.
Appreciate any advice.
2001 1.8 Engine cooling fans - DP
One fan is linked to the air-conditioning system and if it comes on with the AC, it's working correctly. I believe it is also a conventional cooling fan (i.e. it performs two functions)

The other fan should cut in when the coolant temperature reaches a prescribed level. If the gauge is staying at midpoint, this suggests the engine is not getting hot enough for this to occur.

If the gauge was climbing and the fans not cutting in, I would suspect a fault, but as the engine is apparently running at the correct temperature, it seems all is well.

Cheers
DP
2001 1.8 Engine cooling fans - miegas
Thanks to your fast reply, DP. I hope it is the way you say it is.I just don't want to overheat the engine. I just bought this Focus. Maybe it's normal that temperature indicator is in the midpoint and fan doesn't turn on.I don't really know.My previous car was VW Jetta and its' cooling fan was turning on quite often.Well, Jetta was very old car(made in 1988, but very reliable though), so I think it's quite a difference between these two cars, so they may behave in a different ways at some points too. But there's also a possibility that the temperature indicator is showing the wrong temperature, 'cause my speedo is dropping to a zero position intermittently while driving. But when I open my bonnet, the engine looks quite hot. I just wonder maybe it's typical for all Focus'es that the cooling fan doesn't cut in while the temp indicator is only in the middle position, maybe it cuts in at higher temperatures?..
2001 1.8 Engine cooling fans - DP
The standard dashboard temperature gauge is a vague instrument, but on most cars I've owned, the fans don't kick in until it's reading between the 2/3 and the 3/4 mark. .

Bear in mind when a cooling fan cuts in, it should cut out again after a short period. They are only designed to bring the temperature down and cut out again afterwards.

Also the air-con fan will pull some air through the radiator, and will therefore reduce the requirement for the main cooling fan to come on.

With regard to gauge positions, my current Volvo S60 (2.0T petrol) sits at a needle's width over half regardless of what the engine is doing. The digital gauge on our Scenic always shows the same number of segments, and my old mk1 Focus (diesel) never went over half way and never used its fans in all the time I had it. My old Mondeo on the other hand would fluctuate from half to 3/4 quite quickly depending on driving / traffic conditions.

Cheers
DP

Edited by DP on 08/05/2008 at 16:59

2001 1.8 Engine cooling fans - Screwloose
miegas

The gauge and fan control on a Focus are both under direct control of the engine ECU.

No matter what the cylinder head temp sensor does, the gauge displays what the ECU wants to tell you. If it can't hold the line, using one - or both - fans; then the gauge will be swung to the red in 20 seconds. The gauge isn't showing the actual, constantly varying, head temp; it's now just a driver reassurance/warning device, like a red light.

I've had to check the fan operation on several Focii in exactly similar circumstances - the owners think they're not working. Sitting there with a scanner reading the actual head temp in live-data, it's amazing how hot they get before even one fan comes in - 122 deg C!! Even as the fan cuts in and it drops back to 95, the temp gauge never moves.
2001 1.8 Engine cooling fans - miegas
Thanks folks for your help!
 

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