Thermo Swtich Location at bottom of radiator?

**ZZT231** · 13-04-2006, 10:57 AM

Hello All,

One of the guys I was talking to told me as an idea to place a thermo switch/sensor for the thermo fans at the bottom of the radiator and replace the drain plug with the actual sensor... is that an idea or is it a bad idea instead of getting the radiator redone with a thermo sensor mounted on it?

Cheers.

**Rodger** · 13-04-2006, 11:42 AM

ZZT231

If the thermo switch assembly has a themo couple, then this is to go into the top radiator hose. This is the inlet from the motor and as such is the hottest water to measure.

I simply slip it in the hose from the radiator neck end back towards the thermostat then add a little silicone sealant around the neck where the clamp will hold the hose.

If it is a self contained unit then it needs to go above the thermostat somewhere and the radiator may well need to be modified.

You could get away with placing a self contained unit in the outlet/drain plug hole and then adjust the temp setting to come on at the right time. It will need to be adjusted to a low temperature value as the water there is at its coolest.

Regards

Rodger

**WDE_BDY** · 13-04-2006, 11:57 AM

Depends on the temperature of the switch, my car runs the fan switch in the bottom of the radiator with no problems but I believe the temp it switches at is a little lower to suit. Given the fan is designed to increase the temp drop of the water through the radiator, it make sense to ensure the water is cool coming out of the radiator as opposed to hot going in.

Callum

**Rodger** · 13-04-2006, 12:14 PM

Ok,

My take on the whole temperature thing is to measure the coolant coming from the motor at its hotest after the thermostat. It doesn't make sense to me, personally, that we need to ensure the water is at the coolest possible before going back into the motor.

But I can see how it can be made to work.

Regards

Rodger

**ZZT231** · 13-04-2006, 02:04 PM

Ok, it was a stupid idea, I'll get the radiator modfied with the sensor on the top of the radiator tank when I get the money to do so...

Originally Posted by Rodger

ZZT231
If the thermo switch assembly has a themo couple, then this is to go into the top radiator hose. This is the inlet from the motor and as such is the hottest water to measure...

I used to have that Rodger, but now I want to remove it so the engine bay looks OEM and not have an eye sore in the engine bay. This is what was in my engine bay...

**CrUZida** · 13-04-2006, 02:18 PM

I don't think the thread pitch on the drain cock is very thermofan switch friendly.

From memory its about 2.0mm pitch, but I'm not going to remove it just to check

**allencr** · 13-04-2006, 10:56 PM

Thermo Swtich Location at bottom of radiator?

YES!!

Water exiting the engine will Always be above the fan switch temp setting if there is a thermostat, so it would be running constantly after the thermostat opens.
The water entering the engine should be relatively cool, and if it isn't, it'd be from a lack of airflow through the radiator(if no other problem) and time to turn on the fan/s.