Thermo switch/ cooling/ E-fans

[profile18]

So i am in the process of squaring away my cooling system on my 89' UZ swapped cressida. My question to you guys is what Thermo switch do you guys mostly like using or recommend? And what's a good way to wire in the electric fan?

Just connect the ground wire to the thermo switch and the power wire to the battery? so when the thermo switch turns on at a certain temp it just grounds out and the fan turns on?

Ive been looking at SW1802 Wells thermo switches, with a thread pitch of M14-1.5 so it can bolt right into my thermostat housing. Also an operating temp of (on at 200f [93c] and off at 185f [85c]) which could be grabbed from auto zone for about $30.

Would that be a legit thermo switch for my application?

Your feed back is greatly appreciated.

 

[pajman]

http://www.autospeed.co.nz/cms/A_112617/article.html
I'm using this , they hold their programme with the ignition off , you need to drive a relay to turn the high current fan on but it works well . A plus is you can see the temperature in digital. They're on eBay.

 

[profile18]

Thats actually really sweet, cheap and The operating seems pretty straight forward too. Where did you mount your temperature probe? or can you just cut it off and splice in the gauge temp wire?

 

[George_R]

Original temp sensor for UCF21 screws somewhere on the bottom of the radiator, i.e. it sees the result of fan's work, rather than the temp of coolant that's input to the radiator. for on/off swith, operation principle is the same except for it's on/off action

 

[profile18]

Thats a good idea, i'm just not sure on how or where i should mount the temp probe that comes with the Willhi temp controller/display being that its just a probe and isn't a bolt etc...

 

[George_R]

I think you may attach it to bottom side of the radiator and make sure ram air and fan air non't flow directly on it

 

[profile18]

Shouldn't it be mounted inside the radiator and be submerged in the coolant to get an accurate reading?

 

[George_R]

It's better done the way you said, but touching radiator is enough up to my experience.
I once efi'ed a carby engine, I put water temp sensor for EFI in place of dash sensor, undone the dash sensor, and mounted its sensing element somewhere on the shortblock. Reading was absolutely the same after that. So I assume the method has enough accuracy, keeping in mind that the cooling on/off temp seems to be adjustable

 

[profile18]

I guess you're right, i'm just skeptical about mounting it on a surface rather than submerging it because of the airflow the radiator gets, but it could just be me.

 

[George_R]

I just cant'see how it can be submerged in coolant while keeping everything reliable (no water leaks etc). I would say it's ok just to touch *cold* side of the radiator (that near the outlet hose) and find a way to check for wrong readings (sensor wire disconnected, sensor suddenly unbolted from radiator, etc etc)

 

[profile18]

Yeah i don't see any way to submerge it without leaks either, im curious if i can just remove the probe and attach the wires onto a thermo switch or splice them onto my temperature sending switch that's going to my gauge cluster.

How would you mount the probe to the radiator if you were to do it?

 

[profile18]

I guess i could just put the probe between the radiator blades next to the lower radiator hose inlet like this.

and make some kind of mini shroud to block airflow only where the probe is.

 

[George_R]

I would go that way if the sensor fits there. Only fix the wire somewhere near the sensor, so the wire won't make a big loop that oscillates and eventually breaks near the sensor.

 

[Zuffen]

I've run my 1uZ for years with a surface sensor.

I have a length of stainless pipe in my top hose.

The sensor is on the stainless and held in place by a short length of radiator hose and a hose clamp.

It doesn't matter if the reading is (say) 10degress high or low as you can adjust the fan cut in/out point to suit what you want.

 

[profile18]

GeorgeR, yeah that makes sense, i would probably mount the wire securely, along the radiator, and into the cabin.

Zuffen, Do you have pictures of your set up? and it sounds like thats just the way i'm going to go, just surface mounted probably within the radiator fins. With a mini shroud in front to keep cool air from getting to it.

 

[pajman]

I haven't connected the sensor as yet , but I intend to use an inline hose connector that has a 1/8 thread for a sensor , but what I'll do is use the supplied bung , drill it out and glue the sensor probe into that http://s1305.photobucket.com/user/nvmpaj/media/image-5_zps51150c23.jpg.html

 

[profile18]

Yeah the an inline hose connector is also what i was thinking if i wanted to submerge the probe, Just drill a hole small enough in the bung just for the wire and use High temp RTV to seal it up.

 

[GhostRunner]

I have used the same unit.
All I have done is use an old coolant temperature sensor.
Broke all of the plastic and guts out of it then drilled and tapped the crossover
manifold right behind the thermostat.
There is a nice flat spot there for it.

 

[pajman]

Yes did the same the other day in the end , but on top the engine is a large bung that I swapped for a t and screwed the sender in one end and my O/D temp sensor in the other . I'll post a pic later today.

 

[pajman]

Here's my thermo fan probe mounted

http://imageshack.us/a/img822/5281/g4gw.jpg