Hey there

Just updating the news on my electric fan sensor location thing.

As you may have read, I fabbed this waterneck:



and after driving the car around more than 60 km in town, I notice that the action of the sensor is more consistent in this location, right near the thermostat. Actually it kicks in less than when it was on a T at the top rad hose. The amount of time that remains working when I stop is about right, not too long, a few minutes less than the previous setup (I think that the fact of airflow from the fans actually doing its share in cooling the sensor itself externally), no hot starts issues, great!

In fact I think is "the"spot for installing the sensor if you wanna go top of the cooling circuit (we have discussed the top or bottom placing on another topic)

Nos as far as the waterneck is concerned, I did 2 of them: one that shows in the pix wich has been drilled to accept a brass coupler I lined on my lathe (but you can get at any hardware store, I just like it complex ) and the other one was an attempt of lining a flat surface in the lathe then drill and tap the cast iron walls... maybe I'm using a big sensor (threaded portion is 22mm x pitch 1.5 all in metric sys) but when you obtain the right amount of flat surface so the sensor can seal, the walls to tap are too thin... Maybe a smaller sensor wouldn't be an issue, anyway, I recommend to weld a brass fitting for the sensor rather than to tap the waterneck.

_________________
Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Kinda off-topic, but...
Where would be a good, easy, under-the-hood place to connect the power feed for an electric fan that would only have power when the ignition is on?
Mine is currently (pun intended) connected directly to the positive post of the battery.

_________________
aed
/6>V8

The best way would be to use a relay. The "control" signal for the relay could come from the ignition circuit. Then feed the heavy power supply to the relay from the Batt terminal of the alternator (or from the battery as you have it, although that puts more load on the wiring from the alternator to the battery). That way, the heavy load of the fan doesn't have to pass through any of the old wiring or the (relatively small) ignition switch itself.

_________________

Not off topic... just talking about the same.

I agree with 440 mag about the need of a relay.

My setup is connected this way:

I have a 70 amp relay triggering my 2 fans. I wired the (+) side of the "cooling sys" straight to the battery (meaning: the relay and the fans are connected directly to the battery) and I wired the sensor this way: one terminal is grounded, the other is connected to a simple inversor toggle switch underdash. The swith itself has: the center connected to the relay trigger terminal, one end grounded and the other connected to the second terminal coming from the sensor. This way, if the toggle switch is on one end, is ON permanently regardless of coolant temp, in the middle is ALWAYS OFF regardless of coolant temp and the other end is sensor controlled. If I'm cruisin on the higway I have the option of turning it off, or if I park and she's gonna be sitting long enough to not have hot start issues, If I'm at a traffic jam I can have it always on, or say if the sensor fails, or I just can leave it sensor controlled for everyday regular driving. And the nice thing of having the (+) side wired as shortly as you can is that if you have a short, the worse thing it can happen is that you have your fan on till it sucks the battery dead, that can always be fixed easier than melted wiring...

As a general rule, I don't connect nothing to the ignition feed circuits. I'd rather use the accesories circuit un the ignition switch if you wanna get ignition controlled fan operation.

_________________
Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.

Sounds good.
I don't think I'll use a switch under the dash, though. I'd rather come off something in the engine compartment.
What about the starter solenoid?

_________________
aed
/6>V8

If you don't want to break into the engine bay, I think that starter solenoid might be OK... I'd say anything BUT the ignition feed.

_________________
Juan Ignacio Caino

Please use e-mail button istead of PM'ing. I do log in sometimes but I'll be answering quicker thru e-mail.