Technical Cooling Fan Still not working

[alfa156v6]

I assume that the circuit is Ok as I can bridge the connectors and the fan works.

I don't have a proper meter as such just a circuit tester, is that sufficent to test it I assume that it should show a circuit when boiling?

 

[rallycinq]

Yup, should show a circuit.

Cheers

D

 

[alfa156v6]

Does the water actual have to be boiling to do the test I have tried water from a just boiled kettle and neither switch shows a circuit.

Not sure if this is suffiecent.

Cheers

 

[rallycinq]

Does the water actual have to be boiling to do the test I have tried water from a just boiled kettle and neither switch shows a circuit.

Not sure if this is suffiecent.

Cheers

Should be sufficient. Switches are inoperative.

Cheers

D

 

[alfa156v6]

Thanks for the support, I will order a new switch and update this thread if I get it fixed.

Cheers

 

[alfa156v6]

Guy's just thinking out loud to try and understand what has been happening any views welcome.

As I remember the fan used to come on but not for long enough to cool the engine properly or so It would seem (I have a post a few months ago to cover this).
As the fan hasn't worked for a while I can't be sure if the head gasket had already gone or this problem caused the gasket to fail.

Lets assume this means the switch was OK originally surely at some point with the water circulating and all hoses to hot to touch the fan would still kick in at stand still, although probably not long enough to cool the overheating engine due to the head gasket problem and slow circulation at idle.
What I don't understand is how would a faulty head gasket stop the fan from working, presumably it doesn't and that due to the localised boiling and the water in the rad being cooler it eventualy cooks the head.
Going through my reciepts I find I have tried two new rad switchs in the past both of which wouldn't work which seems rather a coincedence.

Therefore based on the discussions in this thread is it possible that the switchs are getting fried some how (electricaly), and if so what might be the likely cause or am I just plain unlucky.

Your thoughts welcome.

 

[fingers99]

Thermostat? Does the top hose get hot?

 

[alfa156v6]

Top hose does get hot.

However the plot thickens, ordered new sensor from on line web site different source but same make as the other new one that is faulty and guess what still does not work so here is what I did to test it.

1. Remove New sensor from car
2. Does fan still work - short wires fan comes on - Yes
3. Remove plug from end of cables and fit wires directly to sensor
4. Dangle sensor in boiling kettle for 15secs
5. Does fan come on - No
6. Swap wires around (shouldn't make any difference)
7. Dangle sensor in boiling kettle for 15secs (edit - tried on a rolling boil for 40secs after prheating for a minute)
8. Does fan come on - No

How long should it take for the sensor to work.

Or is it yet another duff sensor???????? edit - spoken to supplier and desrcibed above and he is sending another foc.
If that don't work then I am at a complete loss regarding what to do next.

 

[alfa156v6]

In the interest of closing out this thread for future reference, I thought I let everyone know what the problem and eventual resolution was.

It turns out I was NOT bleeding the car properly as every time I tried to bleed the car I was taking the expansion bottle cap off so I could poor the drained coolant back in.
This of course meant the system de-pressurised and therefore no air was forced out.

Anyway the good news is it's now all working (except as I am now using a genuine rad switch the fan doesn't kick in till the gauge shows 100 deg), I may fit a relay and manual switch as well once the weather warms up.

Of course I know have several switches to dispose off, ebay here I come.

Thanks to all those who provided advice and guidance.