Electric fan thermostat install
 

I have a question about where to install the electric fan temperature sensor. Should I install it on the thermostat housing monitoring the temperature of the water going to the radiator. Or on the water pump housing monitoring the temperature coming out of the radiator?

There are two outlets on the water pump I can hook the sensor into. The one on the front will have a constant flow of water across it, the one on the side I have to put a tee on there to run my temperature gauge and the fan temperature sensor. The one on the side will not have a constant flow of water across it it's a blocked line. If I put it on the thermostat housing I feel like I need to put it on the front hole where I have to put an adapter but it will have a constant flow of water across it to get a constant correct water temperature.
Am I thinking correctly that it needs to go on the thermostat housing on the front what will get a constant flow of water across it?

Re: Electric fan thermostat install
 

Best for the fan to know the temperature of radiator water. You can unscrew the radiator empty valve at the bottom and plumb in another place for the sensor. You could have your radiator man add a screw-in outlet at the tank (talk to your radiator man). Or you could fashion something in the hoses. I've seen that done but was leery. My former car which shall remain nameless had the first technique, sensor at bottom of the radiator. A second fan was activated if the a/c were turned on.

Re: Electric fan thermostat install
 

That will be easy to do. There's a plug in the water pump where it pulls radiator water to it. I can just put the sensor there

I also just thought of the location for the temperature sensor in the back of the motor also in the head. I could put the sensor back there so it knows the temperature of water in the back of the motor.

Re: Electric fan thermostat install
 

The sensor needs to be placed where the water is the hottest, i.e. right before it goes into the radiator.

Re: Electric fan thermostat install
 

I have mine in the thermostat housing, set to come on ten degrees after the t-stat opens. 180 degree thermostat, 190 degree Spal fan stat. Fan seldom runs except real hot weather and slow driving, never gets over 205. I have a manual over ride switch but never use it

Re: Electric fan thermostat install
 

Since you're in the process of setting the system up, I would definitely recommend adding a manual switch in case of failure. The black box that controls the fan in my street rod failed while on a long cruise. Fortunately the fan was wired into the A/C system so I was able to get back home.

Re: Electric fan thermostat install
 

Ahh, the chicken or the egg. It was explained to me that the thermostat controls engine temp so logically the sensor would want to know the water temp at its coolest that would be at the bottom tank. No point in running the fan if the radiator is rejecting the heat load on its own.

On my 49 I have a Taurus 2speed fan (shroud was made for an 8BA radiator) controlled by a Wreaking yard Volvo fan controller and 2 sensors in the bottom of the tank (185 on and 195 on).
Since the Taurus needs about 50 amps I put a later 160 amp Ford alternator in place of the genny. All this was prep work for the AC.

Re: Electric fan thermostat install
 

This is correct in my opinion and the way I've been doing it for years on my own cars. It takes into consideration the ram effect of the air through the radiator as you are moving down the road.

Re: Electric fan thermostat install
 

Be sure to operate the fan thru a relay. Most fans draw lots of current, and can cook a non-protected thermostatic switch.

Re: Electric fan thermostat install
 

Any electric fan I have installed used radiator temp to control it. I agree with the extra manual on/off switch.

Re: Electric fan thermostat install
 

Right or Wrong. I have 2 elect fans with temp control sensors on my 39. First is in the pass side head that controls the top fan. The other replaces the driver side radiator drain valve to control the bottom fan. The pass side also has a ON/OFF switch. Stock temp gauge on driver side head.

Re: Electric fan thermostat install
 

The package I bought to install this has a circuit breaker, relay and the sensor. I am going to install a toggle switch to bypass the sensor. That just makes good sense to me. I'm glad willowbilly3 and expavr brought that to my attention.

Re: Electric fan thermostat install
 

I go with the bottom of the radiator, so the fan kicks in when the radiator isn't removing enough heat. This is what the fan is meant to do, supplement the cooling system, i.e the radiator.
Martin.

Re: Electric fan thermostat install
 

FWIW, Ford offered an electromagnetically controlled fan as an accessory in about '46-8.
They put the thermostatic switch in the lower left hose with an adapter similar to those used for heaters, since the early pumps had no port for these purposes.