Electric fan 1.8 T Problem

[bilsan330]

Hi Guys apart from my continually water leak.....There is another problem I have had for ages....

from cold the engine gets up to working temp then the electric fan comes on. The temp gauge drops to zero.. I then have to turn the engine off wait a min start up and it resets its self.Fan goes off the temp goes back to normal unfortunately this can happen 2/3 times on a journey.

I have heard people on here talk about a resistor....I want to replace this as the first option...any photos where it is or the name or part number.

Thanks

Bill

[SD1too]

Bill,

I would get your coolant leak fixed first before worrying about the fan and the gauge.

Originally Posted by bilsan330

I have heard people on here talk about a resistor....I want to replace this as the first option...any photos where it is or the name or part number.

Before diving into another project Bill, you should determine that your existing resistor is actually faulty. You can do this by starting the engine from cold and pressing the windscreen demist button on your air conditioning control panel. Then get out of the car and walk to the radiator grille. Can you hear the fan running continuously?

Simon

[T-Cut]

Originally Posted by bilsan330

from cold the engine gets up to working temp then the electric fan comes on. The temp gauge drops to zero.

You have an intermittant fault in the coolant temperature sensor wiring/connector. Vibration is the usual trigger for this, though I suppose the under bonnet temperature could play a part. Check the push connector first. Here it is:

[bilsan330]

Thanks where would I get the sensor from and is it easy to fit..What would I ask for if i ordered one...

Bill.

[T-Cut]

Originally Posted by bilsan330

Thanks where would I get the sensor from and is it easy to fit..What would I ask for if i ordered one.

The important clue is the temperature gauge falling to the Off position. That's from the loss of signal from the sensor. Because it doesn't 'know' the engine temperature, the ECU responds by tripping on emergency high speed cooling.

In nine cases out of ten, the push-on connector needs cleaning. They become coated in oily grit which gets vibrated into the plug. Get a can of electrical contact spray (eBay, Halfords) and give the connector plug and the sensor pins a good sousing. Check that the plug feels nice and solid when pushed home. If that doesn't fix it, trace the wiring back from the plug to the main harness. There may be an intermittant failure in the wiring from vibration fatigue. Some owners have had to tease apart the harness a few inches to get to sound wiring. However, I'd say that's much less common than connector/plug issues. You'll notice that the fan will run at high speed if the sensor plug is disconnected and you start the engine. Reconnect the sensor and it should be back to normal.

As to the low speed resistor for the radiator fan, check whether the one fitted is the original thin(15mm acress, 10cm long) aluminium one or the much larger gold coloured uprated alternative. You need the gold one. It's located behind the fan blades at the 2 o'clock position. You have to look through the front grill and maybe require a good torch to see it. Use a thin stick to turn the fan blades if necesssary. An uprated 'gold' resistor can be obtained from electronics outlets like Farnell, RS Components, or from forum traders and from eBay. Fitting information is easily located. It requires you to remove the front bumper panel. Again, this is well documented with HowTos on the forums and YouTube videos.

In the unlikely event that the sensor itself is faulty, you can get these from Rimmer Brothers and most of the major spares outlets online. The part is called the coolant temperature sensor. The MGR part number is MEK000030 and there are many equivalent alternatives so prices vary widely. Click this.

To fit one, you have to drain some coolant off and collect it if you want to reuse it. The sensor screws into the cylinder head at the right hand end as you look at it. Refer photo above.
Top up with the collected or fresh coolant and bleed as necessary. You should also buy a Haynes Manual


TC

[bilsan330]

Thanks very informative T Cut...I am going to try the cleaning of the sensor first...I wil let you know how I get on.

[bilsan330]

Hi T Cut..

I think you may have found my problem which I thank you for.

Although I did not take the sensor switch out from the socket. I did clean it on the outside with a little WD40......and guess what trouble free motoring for 2 days.

So this is obviously where the problem is.....I am going to monitor it for another couple of days and see whats happens. I may even deside to replace the sensor....

However I still have the underlying problem where the water goes...thats another issue.
Thanks Bill