Installed a Taurus electric fan with a Hayden controller a while back.
It works great, but I was thinking about the best place to mount the temperature probe for the controller.

I installed the probe as the instructions indicated in the rad close to the upper rad hose. While most vehicles use the upper hose as the inlet, the 3VZE uses the lower hose as the inlet.

Would it not be best to mount the probe in the lower part of the rad?

I find that the top portion of the rad gets quite hot long before the thermostat opens up.

Any thoughts on this?

 

bump bump

 

I would mount the probe in the *outlet*... In other words, the hose that brings coolant FROM the radiator and TO the engine. The principle is simple :

The point of the radiator is to cool the coolant, which cools the engine. The point of the fan is to pull air through the radiator, so that it does it's job. However, at highway speeds, air is moved simply by the car getting "pushed" into it. The fan does not need to be on unless the radiator is unable to properly cool on it's own...

So by putting the probe at the outlet, you're measuring the temperature that your system is able to reduce the temperature to... If the system can cool without the aide of the fan, you should leave the fan off so that it doesn't work the alternator, which would in-turn increase load on the engine, and hurt mpg and performance.

However, if the temp is too high on the outlet, the fan would kick on, and help pull air through the radiator.

That's my theory.

 

I would think you would get a pretty big lag time, the temp sensor won't respond as fast as if it were closer to the hot water. If you have an adjustable temp sensor then you can adjust it so the fan isn't on needlessly. I ain't no engine expert though.

 

I can't mount my probe in the outlet as it doesn't like water. But, I think I'll try mounting it lower down in the radiator so I can get a reading when the thermostat opens.