Where to measure Coolant temperature

[TelisSE440]

I've been trying to make my two electric fans run automatically with a fan thermoswitch. Problem is my Electric Pump has only one 3/8 port and i already have  the temp sensor there, the port is located in the left as we see it (pic).

[TelisSE440]

I've been trying to find a way to install the fan thermoswitch, so i looked over the Internet and found this product, which i bought... You install it between the pump and the thermostat housing and it has two 3/8'' ports, in which the installed sensors are just above the thermostat. So far so good...

[TelisSE440]

I screwed the fan thermoswitch there (Be Cool unit - 195 on, 175 off) and i blocked the other port. I turned over the engine and i waited for the fans to turn on. I waited long enough until i saw the temp gauge (stock non Rally Gauge) reach 3/4 and then, afraid of overheating the engine, i shut it off and manually engaged the fans.  I reversed the sensors (fan to the pump port and temp to the neck port) and the fans came on (195 F) while the radiator was still cool. Needless to say, the fans never came off (even when temp gauge needle was on Cold!) only until i turned off the engine and waited about 10 minutes. My question is if it is right to install both sensors at the water neck (as in pic), because i think that the coolant temperature is extremely high in the left of the electric pump and i'm not getting acurate readings. Thanks in advance guys...

[moper]

I'm confused. Why would you run two switches for the fans? Are you running relays for the fans? I would wire the two switched terminals of the relays to a normally open temp switch of the temp you want. When it gets to temp, the switch closes, activates the relay for each fan, and off you go.
It should be take from the water neck - that's where the hot coolant is "fresh from the engine".

[TelisSE440]

I'm confused. Why would you run two switches for the fans? Are you running relays for the fans? I would wire the two switched terminals of the relays to a normally open temp switch of the temp you want. When it gets to temp, the switch closes, activates the relay for each fan, and off you go.
It should be take from the water neck - that's where the hot coolant is "fresh from the engine".

Yes moper, i'm running relays on the fans and i have the ground side of the relays to the fan sensor (sorry, i mean fan thermoswitch). The temp sensor, is just a stock unit for the gauge. I'm understanding water neck you mean at the thermostat side of the pump, as i see in the third picture? If this is the place, then both the switch and the sensor should be installed within the black neck...

[brads70]

I also have 2 fans and use this controller ( and relays) to operate them, Works good! 

http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=852/prd852.htm

[TelisSE440]

That's a nice setup Brad! The unit seem very reliable and easy to operate. Where do you put the temp sensor to measure the temperarute?

[TelisSE440]

Is it that, is the second picture, on the down left?

[brads70]

Is it that, is the second picture, don left?

That is where I installed my old mechanical gauge. It was existing, rad is from a Nascar craftsman truck that never got used. I installed custom speedhut gauges and was not quite sure if I could trust them so I left my old mechanical autometer gauge installed. The sensor for the fan controller is installed in the water pump housing like stock. ( 451",B engine)

[moper]

Gotcha. I get it better now...lol.
They should be in the water neck, or in the pump body in a passage that feeds the thermostat housing.

[TelisSE440]

Ok, I'll install both in the water neck. Although i'm sure that there is a difference in temperature readings, i believe that the engine's temperature is at the thermostat, because its temperature regulating the water passage... Thanks guys