coolant temp sensor

[biffy]

Where is the temperature sensor that is supposed to switch the fans on as mine don't seam to come on. 2.0 petrol.

[Northern Bongolow]

18-840c is the fan switch on here, the other is the temp sender to the dash.

http://lushprojects.com/bongopartsmk2/c ... no=.html#9.

this may help you find where it is, sorry not sure on the 2ltr.

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

the 2ltr runs very cool so this weather they may never come on.put on the air con, do they work then.

[biffy]

Back in the summer we had a European road trip & on the way to Dover we were stuck in very slow traffic & the temp gauge rose worryingly & I never heard them cut in then or since. Some fans somewhere run when the air-con is on cause you can hear them, is this the ones by the radiator or the other one in front of the engine?

[g8dhe]

The ones for the Air Con. are the same for cooling the engine, the two radiators are at the front. So the fans themselves are OK.

[mikeonb4c]

I have a manual over-ride switch for my scavenger fan and wonder sometimes whether it wouldn't be a bad strategy to have the same for the rad fans as insurance against ageing sensors letting the side down. You'd need a coolant temp sensor in theory, though I reckon a TM2 engine block temp gauge could be used at a pinch as a means of deciding if it might do some good to switch rad fans on - the thermostat should prevent the engine getting stupidly over-cooled anyway.

[biffy]

Yes I connected the fans up direct to see if they worked & they did, so is the sensor the most likely culprit?

[mikeonb4c]

Yes I connected the fans up direct to see if they worked & they did, so is the sensor the most likely culprit?

Impossible to say without testing but its worthy of suspicion I reckon. Wait and see what the more technically able on here have to say.

[Northern Bongolow]

as said the 2ltr does run cool but as you have said the gauge went up worryingly when in traffic it sounds like a bit of maintenance maybe in orfer, especially if you dont know when things were last done.

the fans cannot be used on there own to gauge the condition of things as there are several other things that control the temp too. age and condition of the rad, condition and age of the thermostat and the fan trigger switch, and the temp sender switch, age and condition of the coolant. all the above should be replaced frequently , possibly every 2-3 years ,rad probably longer when the water pump is changed.

the fan switch is easy to test if you remove it, it works on resistance so at a known temp there should be a known resistance across it, the plastic end can snap off and wobble, this alters the resistance so makes it switch sooner or later or not at all.

[biffy]

Ok I had intended replacing the coolant along with the termostat in the spring, if I was to remoce the switch (I havn't located it yet) & measure the resistance accross the terminals then heat it up & see if it changes would that be correct? also when i remove it how much coolant would escape?

[teenmal]

Where is the temperature sensor that is supposed to switch the fans on as mine don't seam to come on. 2.0 petrol.

1040/10-180 drawing

Item No 18-840c

http://lushprojects.com/bongopartsmk2/c ... mgno=.html

[jimmo62]

I've tested a brand new genuine sensor and I can send you a graph of resistance against temperature if you PM me your email address so you can check yours but to be honest if you are draining the system you might just as well put a new one in while you're there