Fan controller

[Jstanding]

Happy Holidays all. During the winter down time i might add a fan controller to my electric fan. The donor computer and harness aren't playing nice and the fan is on all the time preventing it from coming up to temp. If i cant figure out why this is happening i will likely add an aftermarket controller. Does anyone have any suggestions on one that works well. I would prefer one that doesnt have the probe that slips in under hose since i have had bad luck with those in the past. If i remember right there is an extra bung in the radiator for a petcock on the top side as well that might accept a temp sender. I need to take off car cover to look. Thanks in advance for the help

[Hoooper]

I dont have any recommendation on fan controller but its definitely nice to be able to run the fan at low speed rather than max all the time. That said, it shouldnt prevent the engine from warming up if the fan is running at max. Thats a thermostat issue.

[CraigS]

The one I used isn't sold any more but Summit has several w/ screw in senders. Depending on intake there may be a spare threaded hole you can use. Also there is a T-stat housing you can get that has a sender hole. Try to wire it so the sender is the ground for the relay. This way it's easy to wire a dash switch in also. I find that I like using the dash switch in traffic. this way the temp stays steady instead of cycling up and down between the fan on and fan off temperatures.

[GTBradley]

I did a right up on a fan controller for the Coyote some time ago, but it will work on any engine. It works well for me, hope this helps.

Two stage fan controller (https://thefactoryfiveforum.com/showthread.php?34158-!-Two-stage-cooling-fan-controller-for-Gen-2-Coyote-(will-work-for-any-engine)&highlight=Controller)

[GWL]

I’ve got a Lincoln Mk VIII, High Output radiator fan, 1993-98 that almost perfectly fit my radiator in the Mk IV roadster. This fan has two speeds and a well fitting shroud. I have added a AUTO COOL 85 PWM CONTROLLER that modulates the fan speed from 0% to 100% depending on the temperature of the water coming out of the radiator. It has a soft start so there is no peaking of amps to get it started and then modulates the fan through pulses of current depending on the water temperature. Higher temperature more pulses to speed the fan up. You hook the control box up to the high speed wire and let the control box do the rest. There is an adjustment knob that allows the fan to come on sooner or later depending on your needs. At speed with lots of air coming through the radiator the fan will not run or run if the heat rises. Sitting at idle, in traffic and hot weather the fan will run faster as needed.

I’ve only got 30 go-kart miles on my car so far but it seems to be running great. I’ll work later to adjust it properly. I’ve also got a dash over ride switch with dash indicator light to run the fan at 100% if I want.

Auto Cool Guy
Home Site:
https://www.autocoolguy.com/

Videos on its operation
https://www.youtube.com/watch?v=wsffrymyeKk
https://www.youtube.com/watch?v=Mpo7aBvNIkw

George

[GWL]

The Auto Cool Guys site. His web site, at first, may seem hard to navigate. However, once you learn it, it's easy. On any page near the top below a few pictures, there will be a black line across the page with different links shown. When you click on a link the page does not change, at least not for me. Or so it seems. Just scroll down the page and the information you wanted/clicked on is down lower on the page.

In answer to the original post, click on 'Sensors', scroll down the page and you will find a copper tube with a sensor that is actually in the water flow and measures the water coming from the bottom of the radiator.

There is also a video on his site that compares the Dearle Controller to the Auto Guys 200 Amp Unit.

George

[mike223]

Ideally, you would control the fan off water temp leaving the radiator - not water temp leaving the thermostat housing (entering the radiator).

The water temp leaving the thermostat housing is always going to be (after warmup) whatever temp thermostat you're using - if the thermostat is operating properly.


I installed 2 water temp sensors for my water temp gauge - (switched) - one in the intake, one in the water pump.

I found it interesting to find that water pump temp rises faster on warmup than intake temp.


They both run about the same temp after warmup - but if water pump temp starts rising it's my reminder to manually switch the fan on.


The point of the story is that even the water pump is too far into the system to serve as a good sensor location for controlling the fan.


Ideally you would sense water temp in the bottom (return) hose, and probably bring the fan on probably no later than 120~130(F) degrees at that location.


Not commonly done, but that would be the ideal way to control what you're actually trying to control with the fan.


The closest option I've seen used is to put the fan sensor in the radiator header on the side with bottom radiator hose - but you certainly don't want that option set for 180(F) degrees.


This is perfect:


I have added a AUTO COOL 85 PWM CONTROLLER that modulates the fan speed from 0% to 100% depending on the temperature of the water coming out of the radiator.

[niceguy]

Call Mark at Breeze Automotive, I purchased my fan controller from him years ago. His has a probe that goes in rad fins near the outlet. Settings are variable.

[CraigS]

Ideally, you would control the fan off water temp leaving the radiator - not water temp leaving the thermostat housing (entering the radiator)...


I can't see why I would care what the water temp is coming out of the radiator after it has been cooled. That is about as far away as you can get from where the temp is critical- the heads. And set the fan to come on at 120-130? Why? Is there something that says the engine will always run at 60 deg more than the coolant coming from the bottom of the radiator? We run a 180 T-stat (or 190 or whatever the engine is specced for) because that is best for the engine. The fan is only needed after the T-stat is fully open (max coolant flow) but the air flow is insufficient to keep the coolant at 180. That is when I want my fan to start, at 185-190. T-stat is in the intake in coolant coming right from the heads. Temp gauge sensor is in the intake near the T-stat. I see no reason to put the fan sensor anywhere but in the same location.

[mike223]

I can't see why I would care what the water temp is coming out of the radiator after it has been cooled. That is about as far away as you can get from where the temp is critical- the heads. And set the fan to come on at 120-130? Why? Is there something that says the engine will always run at 60 deg more than the coolant coming from the bottom of the radiator? We run a 180 T-stat (or 190 or whatever the engine is specced for) because that is best for the engine. The fan is only needed after the T-stat is fully open (max coolant flow) but the air flow is insufficient to keep the coolant at 180. That is when I want my fan to start, at 185-190. T-stat is in the intake in coolant coming right from the heads. Temp gauge sensor is in the intake near the T-stat. I see no reason to put the fan sensor anywhere but in the same location.

What I am saying is that once the engine is warmed up the water temp throughout the engine stays at the thermostat setpoint.

Once it's above thermostat setpoint you're already on the way to overheating.

Because the return water from the radiator was too hot to cool the engine.

Temp switches usually have a differential of 20-30 degrees - once it reaches your set point of 185-190, the fan is never going off again until the engine is turned off.

Because the thermostat is going to keep the water temp in the thermostat housing at a minimum of 180 degrees (or whatever temp thermostat you're running).

And you'll be fine and never know the difference, but your fan will run all the time once the engine is warmed up.

Which is fine with me.


But the OP wanted to know about fan controllers and what you're actually trying to accomplish with one.

[mike223]

Why? Is there something that says the engine will always run at 60 deg more than the coolant coming from the bottom of the radiator?


You're thinking about this the wrong way.

It's the limit of how much heat the radiator can shed - and how quickly it can shed that heat load.

Which happens to be about 60 degrees - with the fan running.

Once it has shed that 60 degrees it doesn't need the fan running anymore.


But the intake + thermostat housing are still going to be at thermostat setpoint if the thermostat is operating properly.

[Richard Oben]

Hayden 3647 controller ($30 =/-). It has an over ride for AC which can be used for manual, or for AC. Probe goes in the fins on radiator. Read the directions!

We put inboard and down from outlet a few inches. Adjust so it comes on once after engine shut off and of course on engine temp. We have never had one over heat with this controller. We also never use under drive pulleys on a street car. Pretty but useless, do not push enough water at idle, no matter the fan speed. HTH, Richard.