thermostat switch

[Dirka]

where do i put my thermostat switch for my electrical fan? lower radiator house after the thermostat or where???

[jrhone]

Get a water neck with 2 ports. One for the temp switch and one for the fan switch. A standard BMW temp switch fits. Wire it up and it's nice and clean....

[pkbinplano]

Hayden sells a kit with a probe that slides through your radiator. Conects to a little black box that has an adjuster to set the temp when you want the fan to kick on.

[///mChris]

Mine is in the radiator drain plug location. I would think you'd want it at the exit of the radiator. Which way does the water flow through the radiator?

[Guest Anonymous]

There's a emissions related threaded temp sensor on the bottom of the front-most intake runner. I installed a switch from a 320i in that location and it works well.

[beammmer]

Get a water neck with 2 ports. One for the temp switch and one for the fan switch. A standard BMW temp switch fits. Wire it up and it's nice and clean....

What vehicles have the 2 port water neck?

TIA

Don

[BDB]

I am wiring my Hayden controller as we speak. I followed the instructions which say to put the probe near the inlet side (top hose).

[wegweiser]

If you use the fan switch from a later BMW (one that uses TWO switches in the radiator for instance) and choose to put it in the upper aluminum water neck (as found on tii, etc), you *might* want to have the higher temp switch (ie: for HIGH fan speed) as the neck gets hot awfully fast,,,I had mine wired like this with a relay, etc and with the lower version of the temp switch, the fan came on way too often IMHO. Drove me nuts!

HTH!

[jrhone]

Get a water neck with 2 ports. One for the temp switch and one for the fan switch. A standard BMW temp switch fits. Wire it up and it's nice and clean....

What vehicles have the 2 port water neck?

TIA

Don

Tii's and E30's I think. Mine is also angled so I can easier fit sidedrafts. Bought mine from a FAQer.

[Zenon]

If you install your fan thermoswitch or sensor anywhere other than in the bottom or outlet of the radiator (i.e. where the water that has been cooled is), then you are kinda' sorta' missing the point of having an electric fan.

A sensor in the water neck is going to either make your fan run all the time (inefficient) or only after the engine t-stat is fully open and the engine begins to overheat (not ideal from a temperature regulation point of view, and that is assuming you set the trigger point just right). The latter may be acceptable in that it still prevents boiling over, but just because some manufacturers do this does not make it ideal - they do it because they can save on the cost of a sensor and some wire.

[TobyB]

yeah, I use the 'drainplug' version from a 320, and it's a 190f switch...

...and yep, it's in the drainplug location!

t

[AceAndrew]

If you install your fan thermoswitch or sensor anywhere other than in the bottom or outlet of the radiator (i.e. where the water that has been cooled is), then you are kinda' sorta' missing the point of having an electric fan.

.

Uhm, kind of got it backwards there,

I'd want my temp sensor reading coolant as it comes out of the engine indicative of the coolant temp inside the engine. Best place for an inline type temp sensor would be on the upper radiator hose.

I like John's setup, very slick. But you could go with the IE inline adapter for $12.00.

[Zenon]

If you install your fan thermoswitch or sensor anywhere other than in the bottom or outlet of the radiator (i.e. where the water that has been cooled is), then you are kinda' sorta' missing the point of having an electric fan.

.

Uhm, kind of got it backwards there,

I'd want my temp sensor reading coolant as it comes out of the engine indicative of the coolant temp inside the engine. Best place for an inline type temp sensor would be on the upper radiator hose.

Umm, not if we are talking about controlling a radiator fan. Think about what the radiator does, what the radiator fan does, and then when you would want the fan to operate, and when not. Then think about the best place to measure temp to determine if the fan is needed.

If you are talking about a temperature gauge or ECU engine temp sensor, then sure, the engine's coolant outlet is where you want to read temp.

Lots of confusion here.

But at least that inline sensor hose fitting would work at the rad outlet, too, and be ideal for a FAN control sensor.

[///mChris]

I completely agree that the switch should be in the radiator.

I always liked my thermodynamics classes in school. Essentially there is a cyclic process that is used to remove excess heat from the motor. The engine heats up the water and the radiator cools it. The water flows in one direction and is driven by the pump. The amount of heat removed from the water is a function of the speed of the flow of water (which changes with engine speed) and to cooling capacity of the radiator.

In my case, I have a silicon garage radiator and the electric fan rarely kicks in. The radiator has enough cooling capacity to take the high temperature coolant from the top and output with a much lower temperature. If the cooling capacity of the radiator is not great enough, the output temperature isn't going to be low enough. In that case you want to kick the fan on to provide additional cooling.

The thermostat regulates the temperature at the top of the radiator. In the case that the output of the radiator is getting close to the input, you still couldn't tell that their is a problem. The only way you'd know you need to kick in the fan is when the thermostat is fully open and the radiator's output temperature is higher than the thermostat's temp.

In my opinion that is too late.

[Dirka]

THANKS, I do have the inline adapter from IRE and thank you all for the advice