Thermo Switch - where to mount in cooling pipe

[MrOizo]

I am have installed a Davies Craig thermal switch installed on the top pipe from the radiator pipe.

I was wondering if this was where the switch should be and also what temp i should have it set to.

The electronic fan looks like it is to come on at 97 degrees and go off at 88 degrees.

I was thinking that i should have it on the bottom of the radiator and set it to about 90 degrees. mounting on the bottom might be better as the switch would be out of the way..

hmmm...

[Rob]

Most have them in the pipe out the back of the head, also this would not work on a RWD I suspect. The other place is normally in the bottom tank of the radiator on East West mounted turbos such as ST185 and ST215 so the bottom hose should be fine

[MrOizo]

Most have them in the pipe out the back of the head, also this would not work on a RWD I suspect. The other place is normally in the bottom tank of the radiator on East West mounted turbos such as ST185 and ST215 so the bottom hose should be fine

yeah thats what i thought so as long as i get the temp adjusted right i should be fine huh?

cheers.

[Rob]

Yeah should be fine

[MrOizo]

hmm... well i have put it back into the top hose. the thing i have read on other write ups is to have the probe on the top as thats where the other ones are - after the thermostat. but then i got thinking as the switches are on the bottom. i really dont know what i'm doing now :0

the more i think about it... the more i should hav it on the bottom hose

measured the temp with IR sensor and it measured at 75-ish deg on the engine outlet wasnt up to proper operating temp but seemed like it was cooking :/

[Rob]

3S's in East-West format have the thermostat in the front of the motor behind the alternator and all the sensors are in the tree out the back of the head.

When You say it was cooking....Do you mean you had the rad cap off and the water was trying to boil out??? That normally means that you have an air lock somewhere. To remedy this make sure the car is on flat ground(or pointing uphill) put a funnel or a bottle that will fit in the filler sealed with insulation tape and fill the funnel/bottle half way with the heater on full hot set to demist front screen. Once the fan has come on and gone off a couple times then the cooling system should have no air left in it.
In saying this I don't ever remember doing this to a toyota which wasn't a diesel, petrol ones bleed really easy.

This information comes from 2 1/2 years at Dodsons as a mechanic and well over 100 engine swaps so it is tried and true if anyone doubts it

[MAGN1T]

It's not too hard to figure out that the thermo switch is there to turn on the rad cooling fan.

That means it needs to sense the water temp after the rad.

So if it's not in the borttom hose (or somewhere after the rad core), it won't work.

Steve