Electric fan wiring

[zglad]

Hello all,

I have an electric switch mounted on my '40 to help keep the SBC cool. I have an aluminum radiator with a probe that is mounted through the radiator to turn the fan on and off. I also have a manual "on" switch in the cab. I've noticed that my temperature gauge seems to rise above the 195 degrees without the fan turning on. I've tried to move the probe to various locations on the radiator (closer to the water inlet) but I'm still not having any luck with the fan starting without me manually turning on the switch. My question is, if I change to a threaded switch, where is the best location for it? I've considered installing it in the thermostat housing, but then it will only turn on when the thermostat is open and not necessarily when the water temp of the radiator is above the 165 degree set point. I would ideally like to have the fan turn on when the water temp in the radiator is above 165. Once the return hose is empty, the sensor likely wouldn't be reading anything. Am i thinking about this correctly?

Thanks,

zglad

 

[ingomar]

If the thermostat isn't open, you have no cooling flow yet and there is no need for the fan. Some SBC heads have tapped holes that you could plug a sensor in, and most all manifolds do, too (gen 1's, anyway). Pick the sensor trip point to be above the point the thermostat opens. If you run, say, a 170 t-stat, 180 or so would be a good sensor trip point for the fan.

 

[fieldsken1]

get rid of the probe its junk use the painless electric fan wiring thingy it works better. the sensor mounts just off of the thermo to the drivers side. Painless Wiring 30103 - Painless Performance FAN-THOM Electric Fan Relay Kits - Overview - SummitRacing.com

 

[Mark W]

Why are you trying to get the fan to run before the thermostat opens?


If you want the fan to come on at 165... might as well just wire it to run all the time that the ignition is on.


Mark...