Electric fan/thermostat logic

[chimpboy]

Hi all, just trying to get my head around the temperatures that should apply to an electric fan controller and to a thermostat if your only fan is the electric one.

Let's say you have a fan switch that turns on at 85 degrees and off at 80 degrees. Would this suit an 82 degree thermostat, or would it be wrong because the fan keeps running all the time while the thermostat closes up to try to maintain 82 degrees?

What's the rule of thumb?

[Struth]

I haven't thought on this much but I would assume the fan wants to keep the engine warm enough for the thermostat to remain open, thus keeping the coolant constantly flowing through the radiator and cooling the engine.

I thought thermostats were to allow the engine to warm up then stay open ?

Possibly they close as well to keep the engine at optimum operating temperature.

Cooling systems are not something I have needed to play with much.

Short answer then is "I am not sure"


EDIT: from the net "A thermostat is a device for regulating the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature"

This would indicate that the thermostat should open and close during operation. Still haven't helped I know.


Cheers

[-Scott-]

Good question, but does an 82 degree thermostat open/close at 82 degrees, or is 82 degrees the approximate temperature at which the thermostat is supposed to regulate - in which case I would expect it to be "cracked" at 82 degrees.

But essentially, I don't think there's any point having the fan running while the thermostat is closed.

Then again, the only aftermarket electric fan I've had used an adjustable switch with a bulb in the top radiator hose. I have NFI where it switched.

[love ke70]

you would want an 85 90
fan running all the time is unnessecary (and they burn out in my experience)

in a good system, you shoudnt need the fan on at all over 50kph.
cheers, andrew