I am trying to figure out the best way of controlling the electric radiator fans in my 260 Z.  

The previous owner installed dual electric fans operated by a thermostat with a temperature probe in the upper radiator hose connection to the radiator.  The temperature switch no longer turns off the fan so that even when the car is cold the fan is running and I need to pull the fuse.

Would it be best just to replace this with an  identical  unit or should I install a  temperature sensor in  place of the threaded plug of the thermostat housing? If so, does anyone have an idea what the threading is on this plowed?

Thanks for reading this… Jeff 

Pretty sure that they make a controller that uses a temperature sensor.  You mentioned a switch, then a sensor.  With a sensor you need the controller.  With one of those you can set the temperature you want for fan cooling, and some have a timer for after engine shutoff.

Search "Ford Taurus fans" on the internet and you'll probably find some other options.  That's the common setup and control system.

Here's some possibilities - 

https://www.summitracing.com/search/part-type/fan-switches-thermal/thermal-switch-style/adjustable-fan-control-kit/sending-unit-style/radiator-probe

I am going to be at Summit racing tonight to pick up another item. I will talk to their technicians there to see what they suggest.

Thanks… Jeff 

Jeff my sensor is on the driver side of the block. See photo

 

 

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That triggers a relay.

Did the system work before? If it did, I would make it work again. Controlling the fans from the block water temp is a good way to do it...

3 hours ago, 7tooZ said:

Jeff my sensor is on the driver side of the block. See photo

 

 

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That triggers a relay.

Curious what is the sensor from?

On making the old system work again, the old system looks kind of beat up (missing control knob, no enclosure box) and has some odd wiring (one wire going to the coil). I can try and open it up and look for a relay to replace, but I'm not sure if that's the issue. 

Summit Racing had a screw-in sensor that looks like the one 7tooZ posted but it has a 3/8-inch pipe thread. What type of threading is used on a Z? I noticed that 7toZ has a bushing on it. Is that a NPT to some type of metric bushing? If so, where do you find such an animal?

It came with my fan kit. I took out the original plug and took it to the local hardware and matched the treads for both the sensor and the old plug for the adapter.
I think you could use a stock sensor. My automatically kicks on at just over 180 and shutoff at about 180 at the rear of the block.


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5 minutes ago, 7tooZ said:

It came with my fan kit. I took out the original plug and took it to the local hardware and matched the treads for both the sensor and the old plug for the adapter.
I think you could use a stock sensor. My automatically kicks on at just over 180 and shutoff at about 180 at the rear of the block.


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What kit did you buy?  I have one of the flexlite versions you insert into the radiator hose.  It works, I just don't like the way it looks.

The stock sensor doesn't open / close like this sensor would though.  It's like a resistor that the gauge reads right?

2 hours ago, JSM said:

What kit did you buy?  I have one of the flexlite versions you insert into the radiator hose.  It works, I just don't like the way it looks.

The stock sensor doesn't open / close like this sensor would though.  It's like a resistor that the gauge reads right?

The one you have sounds like the one I have right now. I purchased this one:

https://www.summitracing.com/parts/sum-890115

They also sold me a radiator hose adapter to install along with it but I don't want to go that route if there is a way of connecting the thermal sensor directly, especially at $50.

https://www.summitracing.com/parts/atm-2283

The plug on the thermostat housing looks more accessible so I'll unscrew it and take it to a hardware store and maybe I'll bet lucky.

I believe most of the sensor threads are "british pipe thread" - BPT. I beilieve most NPT's can be made to work...

Would that lug on the thermostat housing be on the hot side or cold side? I thought the sensor in the side of the block gave me the most consistent block temp.
Some use a radiator sensor which make no sense to me. Maybe one of the engineers on here could weigh in .


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