Setting electric cooling fan temp. Advice please.

[Sundowner]

Gents,
I read with interest another thread, about Alicool radiators V Standard radiators. It got me thinking that I have only ever set the thermostat roughly on my Sprint since I installed the new Electric cooling fan.
I'd like to go through the process a little more accurately than what the instructions that came with the Davies Craig fan indicate.....
Run the engine until the temperature is about halfway between "normal highway operating temperature" and "too hot". This will indicate a temperature between 5 degrees C and 10 degrees C higher than normal.
The next instruction is to immediately turn the adjustment knob very slowly anti-clockwise, just until the fan(s) switch on, and no more.
Given that my Sprints gauge has a cold mark, a hot mark and 3 marks in between, indicating I suppose, 1/4, 1/2 and 3/4, where would you say is the "Too Hot" mark?
Given also, that the temp gauge used to sit right on the half way marker on the highway before I installed the fan.
I look forward to your suggestions and advice?
Thanks & Cheers,
Rob

[Sundowner]

As I mentioned in the above post the car used to highway drive with the needle dead center before I fitted the electric fan.
It's fitted with an 82 degree C thermostat.
Knowing that, any guesses/estimates as to what the temp might be when the needle's at the 3/4 mark or even right at the top?
Thanks,
Rob

[tony g]

Gauges and senders will differ from car to car but on mine with significant water mods, half gauge is approx 85 and in between half and 3/4 is 93-95 which is where my electric fan comes in. My temps are being measured with k type thermocouples in 3 places and the higher numbers are coming from the back of the head plate. My stat is also an 82.

Tony

[Sundowner]

Thanks Tony,
Much appreciated.
So if I set it up so the fan activates midway between 1/2 and 3/4, that should be OK?
I'm on to it tomorrow.
Cheers,
Rob

[GTS290N]

What about using an IR thermometer, take the temperature of whatever it is your pointing at when running normally, take the temperature when hot, see if it correlates to Tony's K-type readings?
In fact, Tony could you do this, see if an IR meter correlates to your k-types? Given different reflective surfaces and insulation/transmission properties of bits and bobs I doubt the readings would be the same, but if a correlation could be proven it could be very useful for others now that you've done the hard work.

[tony g]

Yes go for that as a test and see how it controls things. One thing for sure is when the fan kicks in the bottom hose temp almost instantly loses 3-5 degrees

Tony

Thanks Tony,
Much appreciated.
So if I set it up so the fan activates midway between 1/2 and 3/4, that should be OK?
I'm on to it tomorrow.
Cheers,
Rob

[tony g]

I have already checked things with IR meters (x2). Very difficult to get accurate readings compared to TC's. I did have some very close readings when moving the IR at differing angles etc. Shiny surfaces give odd results at some angles too. So as a generalisation they can be useful but dont rely 100% on them.
Some stick on k types with hand held reader can be very useful too

Tony

What about using an IR thermometer, take the temperature of whatever it is your pointing at when running normally, take the temperature when hot, see if it correlates to Tony's K-type readings?
In fact, Tony could you do this, see if an IR meter correlates to your k-types? Given different reflective surfaces and insulation/transmission properties of bits and bobs I doubt the readings would be the same, but if a correlation could be proven it could be very useful for others now that you've done the hard work.

[Sundowner]

Today I checked the fan cut in temp.
At idle, in the shed, from cold, the gauge slowly moves up to just below 1/4, then fairly rapidly lifts to around 1/2. From 1/2, it very slowly moves up and the fan starts operating with the needle exactly mid way between 1/2 and 3/4. Using my mates hand held IR temp sensor, its indicating "around" 95 degrees C at the cut in point. The needle then slowly comes back down to just above 1/2, when the fan shuts off again.
I'm happy with this, as long as you gents are. BUT....I've yet to road test it.
Rob

[Mahesh]

Today I checked the fan cut in temp.
At idle, in the shed, from cold, the gauge slowly moves up to just below 1/4, then fairly rapidly lifts to around 1/2. From 1/2, it very slowly moves up and the fan starts operating with the needle exactly mid way between 1/2 and 3/4. Using my mates hand held IR temp sensor, its indicating "around" 95 degrees C at the cut in point. The needle then slowly comes back down to just above 1/2, when the fan shuts off again.
I'm happy with this, as long as you gents are. BUT....I've yet to road test it.
Rob

At idle, in the shed, from cold, the gauge slowly moves up to just below 1/4, then fairly rapidly lifts to around 1/2

My car did the same, (except for the being in the shed part) but I was never happy with the rapid 1/4 to 1/2, as it never did this before.
Unfortunately I can't remember the exact cure, it was either air trapped in the coolant system, flushing of the heater matrix and H pipe,
or I had filled up with the heater on cold.

Most likely none of those apply to yours, but now I have a slow but consistent temp increase to just over the 1/2 mark and then
the fan cuts in, but that "seems correct on my motor", according to my memory as a teenager

[tony g]

Sounds good to me Rob

Tony