So I had a couple of electric fans fall in my lap. I ordered a fan controller and made a shroud and now I've gotta throw it all in to replace the factory viscous fan. I was curious, at what temp does the factory fan engage? Should I set the new dual fan setup to turn on at the same temp? If not, then at what temp would you recommend?

Thanks everyone!

 

I was curious, at what temp does the factory fan engage? it does not engage by temperature

 

How does it engage? I was under the impression that the little thermostat on the front, when heated up, would allow or disallow the flow of hydraulic fluid in the fan clutch, which would then make the fan either run at full speed or run slower than full speed.

 

well to some extent i guess you are right, i've always gone under the impression that it is mostly controlled by inertia and the fluid that they use as it spins and heats the fluid in it gets thinner and the fan stops gripping .
your t-stat opens in the 180-190 temp range so i would think you would want to set it high enough that the t-stat opens in a reasonable amount of time but lower than the 210 that the aux. fan kicks in at.
but i could be 100% wrong

 

So do you think setting the electric fans somewhere between 196-198 would be reasonable? I don't really think they need to be running while the vehicle is moving down the road, but I could be wrong. Right now the old girl sits around 195 running down the road and heats up to 201 at idle.

 

"i" would think that would be a safe place to start

 

That's what I was thinking too....set your electric fan to come on at a little after 195 to keep temps below 200. Or if running a grey 180 maybe on at a little lower.

 

Yes they are Thermostatic. Whats wrong with yours? Your temps are fine..If your adding extra fans to try and get your rig to run cooler, you have another problem with your cooling system.

 

Put simply, yes it works solely by temperature based upon fluid dynamics. As the oil inside heats up in theory it becomes more viscous and 'grips' better the two parts of the void. As it cools it becomes less viscous and the fan slips more and therefore rotates less. All very fickle in practice.

This is a Jag viscous fan and explanation which is very similar if not the same.

Jaguar V12 Fan Clutch

My only issue with electric fans are that if you are in the middle of nowhere and the fan expires you can easily 'lunch' your engine and can do nothing about a burned out electric motor whereas a viscous fan can be modified to run 'locked up solid' and maintain radiator/engine cooling. The only other concept is twin lead lag electric fans where each runs at a duty greater than 50%, ideally 60-65% of total duty and if one expires the other gets you out of trouble at least even if you have to stop occasionally to cool the system down. More ideally would be that they are both 100% of duty running lead lag with an auto speed modulator possible solid state electronics coupled to the engine temperature, complicated, yep very, until you get seriously into hi-end thermocouples and electronic controllers.

 

There's nothing really wrong with mine. I just had this stuff and figured why the heck not? I know, there are a lot of people against this specific kind of change. It's not the first change I've made that has gone against what is commonly known as "correct" in the D2 world. None the less, I've got a hard head an I like to learn most things for my self.

I know it wont add power, I know it wont help gas. That seems to be most peoples reasons for this change and it never helps much. It is supposed to make it idle smoother, however, and I like the flexibility of being able to adjust the temp at which my fan engages. Plus, factory fan is loud as crap.