I have an 81 RX7 Drivetrain in my car. The previous owner removed the clutch fan and installed some weird temp sensor set up. Problem is I cant find a correct replacement sensor for the type he installed. Im trying to find somewhere to mount a regular coolant temp sensor to turn the fan on. I saw there's a sensor in the bottom of the radiator what does that do? Could I tap that some how? I was looking to do a relay and use the sensor to ground out the 85 terminal of the relay.

 

Very simple. Go to summittracing and buy a fan switch and an fog light or automotive relay. I cant remember the spec on my fan switch but i think it opens at 195 and close at 170. Fan switch can be mounted behind the water pump housing or t-stat housing (easiest one to do). connect the relay's 85 terminal to fan switch and on the same terminal, run a wire to the cabin to a 2-prong toggle switch (other terminal to ground) so you can have by-pass switch...in the event fan switch fail, you can still manually turn on the radiator fan.

 

Do I have to drill and tap for those locations? Or do either of them already have an opening.

I was trying to avoid that. I found these adapters made by Flex A Lite you put them inline with the radiator hose and they have a bung in them for the sensor to thread. I've heard it's better to have your sensor in the lower hose. Is that true?

 

Heres the adapter I was looking at this one is made by Autometer but looks a little nicer. http://www.summitracing.com/parts/atm-2283

If it wasn't pouring outside Id go look to see if those spots are tapped on the block.

 

Go with a fan controller from flex a lite. they have a probe that you push into the rad to read the temp.

 

That will work too or the rb adapter for rx-8 heater hose. Behind the water pump housing, remove the sensor and use 3/8 tap. Or the block (front plate) behind the power steering pump/ac bracket.

 

Ive seen the bulbs before, are they reliable? Im driving the car everyday so that is a big factor.

I went outside this morning and aw the sensor behind the water pump, what does the one thats in there do?

 

If I'm not mistaken, the sensor in the rear of the water pump housing releases the magnetic switch on the choke.

Mine was unplugged last night and the choke **** would not stay out when starting a cold engine.

 

i run my fan all the time for now, though i'm going to be looking into setting it up one of these ways on a temp sensor eventually(probably over this winter) as of now i just have a switch in the car that i turn on/off when i start and stop the car

 

Does anyone know if the probe type are reliable? Or is the sensor like I was going to use better?

 

Ok i have a aluminum rad thats v mounted with fan in front as a pusher. I have used a probe type that i got at autozone for 3 years no issues at all. They have 2 types one thats adjustable and one thats not i went with the non adjustable because the probe was made so you used your own wire. The adjustable one they carry has a hard wired probe and the wiring is super thin. The non adjustable opens at 185 which i found to be perfect for my setup. Best of all the non adjustable is only 19 bucks. If you have any other questions i will help all i can.

 

if you use the push in style prob WITH an aluminum radiator the location of the bulb is critical. Youll want it as close to the radiator inlet as possible because the probe will actually cool off where the water (coolant) isnt the hottest, causing the fan to come on late, and not run long enough to actually cool the coolant.

The problem has only been with aluminum radiators though in my experience, since the surface of the radiator seems to cool off much faster than the actual coolant when the air is moving over it.

 

Agreed i put mine about 3 inches below the upper rad hose comes on at perfect time according to an aftermarket temp gauge in the rad.