TR6 Electric cooling fan switch - where is best location to mount?

[sqbsprite]

I have a '71 TR6. I'm looking at installing an electric radiator fan. I like the Hayden sensor that has a 3/8 NPT male fitting as opposed to the clip on sensor. Has anyone installed this type of sensor? The thermostat housing has the temperature gauge sending unit threaded into it as well as a nipple for the heater hose going to the intake manifold. Does anyone know what thread size these are? It would be great if these were NPT type, then I could just install a Tee. I'm not having any cooling problems, but the fan needs to come off to replace the bushings, so it would be a good time to install an electric one.

If you have installed a fan system, I'd like to know which one you installed and how it works. Thanks.

 

[poolboy]

I've had 2 TR6 with electric fans, both had 16" Procomp fans.
The sensor in one was placed in the radiator's upper right side.
The sensor in the other was placed in the metal section of the coolant return pipe.
For all practical purposes there was no difference affecting the efficiency of the fan. When the coolant got hot enough for the sensor to turn the fan on, the fan came on and when the coolant temp dropped, the fan stopped.

 

[Geo Hahn]

Seems like the cars I have owned that had stock electric fans placed the sensor low - i.e. near the return.

I would think you want the fan to run when the radiator can no longer cool enough without it (e.g. stuck in traffic) and that reading would come from near the radiator output.

Of course, another factor is what temp you choose for having it switch on -- I believe you would want a lower temp for the 'down low' position than you would want for the 'up high' position. In the latter case you are looking for overheating rather than inadequate cooling.