Coolant Temp Sensor (Efan Mod)
 

My father and I both want to send our clutch fans to the trash and slide in a used efan in it's place. However, we've run into a hurdle during our research.

We need to devise a way for the efan to know when to kick on, automatic and all that. I can find a plethora of threaded temperature sensors for around 5 dollars from various makes and manufacturers, however the problem is I don't believe these work in the way that we need them to.

I don't know exactly how these sensors operate, but we need something that say, for example, when the coolant hits 185 degrees, then fan turns on (via relay) and shuts back off when it goes below 185.

Anyone got anything? This one's got both of us stumped.

They make adjustable fan controllers that have the threaded sensors to turn on a fan or 2 at whatever temp. you set them to.

Yes, you want a temp Switch for an e-fan, not a sender/sensor(variable) as used for temp gauge

Like this: 185° Degree Electric Thermostat Temperature Switch for Radiator Cooling Fan New | eBay

And then something like this for upper rad hose: Radiator Hose Adapter | eBay
These DO need to be grounded, they will have a screw terminal for ground wire.
The temp switch is open until it reaches the pre-set temp, it then closes and Grounds to the bung(engine), this would Close the Fan Relay and fan would come on.

12volts-------Fan Relay(coil)----------temp switch----------Ground

The 12volts can be 24/7 power or Key On power.
24/7 power allows the fan to keep cooling after you shut off engine, it will then go off when temp drops below temp setting, some like that some don't.
Key On power is fine, that's is what you have now, when you shut off engine mechanical fan shuts off.

Having a manual OFF switch can be handy if you run into high water, keeps engine bay drier since there is no fan spraying the water around.

@Dewey: Wasn't aware they made an adjustible version of the screw-in variety. I'll have to see if I can find one, now I"m interested.

@RonD; Stellar! Exactly what we need.

Thank you both.

I'm a fan of Delta Current Control's controllers. I used to run one on an old truck of mine for years with a 19" Grand Cherokee electric fan and it was rock solid. Not sure if they are still in business.

You might also check out Autocoolguy's controllers too.