If you have made an electric fan conversion where and how did you install a temperature sensor? What temp range have you found works best? I was thinking on at 200 and off at 185? Is that so cold that once they turn on they will never turn off? I plan on controlling both fans with a single relay that is controlled by a temperature switch. i installed a new fan clutch and I hate it. It's loud and killed fuel economy. I removed it and have been driving with no fan for a month. It works surprisingly well. Only gets hot during long idle time and lots of stop and go driving. It seems that electric cooling is the only way to go. Thanks, Doug
Electric cooling fan
- Thread starter Drollins
- Start date
Those temps won't work. The thermostat doesn't even open until you reach 192.
I have a great controller on mine bought from www.DCControls.com
This is a fully adjustable controller that has variable fan speeds based on temp. Not cheap, but a very good controller.
You should probably be looking more in the on at 215 to 220 range. Diesels run hot, don't be scared of that.
My biggest problem so far is finding an electric fan that moves enough air. In th summer here, windstar fans have proven to be not enough.
I have a great controller on mine bought from www.DCControls.com
This is a fully adjustable controller that has variable fan speeds based on temp. Not cheap, but a very good controller.
You should probably be looking more in the on at 215 to 220 range. Diesels run hot, don't be scared of that.
My biggest problem so far is finding an electric fan that moves enough air. In th summer here, windstar fans have proven to be not enough.
BDCarrillo
Full Access Member
I put the sensor up by the upper radiator hose for my fox body electric fan. Idle up the truck and when the upper hose gets hot, dial in the controller to turn the fan on a little bit over that point
I've been running electric fans now on the Moose Truck for many years. I put a 185 degree sensor in the spare water jacket port on the passenger side head, and then replaced the stock 240 overtemp switch in the drivers head with a 220 degree. The lower temp controls the low speed relay, and the higher temp controls the high speed relay. It may be true that some thermostats open later, but it is my experience that you need cooling sooner, rather than later. In my setup, the high speed fan never comes on, unless the low speed fan fails for some reason. When that happens, my engine warning light comes on to alert me that my temps are higher than normal, and that I need to watch my water temp gauge. This is more useful than a light that comes on that says "too late... you overheated your motor" as Ford had intended. 
You also have to remember that your interested in the temperature of the engine and not the temperature of the thermostat. The thermostat is in the hottest part of the engine, and has collected all the heat from everywhere. Where my first sensor is, the water has just come through the block into the head, and is not that hot yet. If you put a 192 degree sensor where mine is, then your engine is basically overheating because the water hasn't been cooled by the radiator yet.
You also have to remember that your interested in the temperature of the engine and not the temperature of the thermostat. The thermostat is in the hottest part of the engine, and has collected all the heat from everywhere. Where my first sensor is, the water has just come through the block into the head, and is not that hot yet. If you put a 192 degree sensor where mine is, then your engine is basically overheating because the water hasn't been cooled by the radiator yet.
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turbo elk
Full Access Member
What brand of fan are you running Mel?
I use two 3.8L Taurus fans. They have 3 wires each, one for ground and one that is low speed and one that is high speed. The way it generally works is like this. If the engine is below temp, once I start driving, even on a hot day, if I'm doing 40 MPH or better, the fan never comes on. Once I stop however, if the low speed fan kicks on, then it's on. It will never go off, until I shut the truck down. But I'm OK with that. It does not draw a ton of current, and after the truck is off, and it sits there cooling my engine compartment for about 5 minutes, it shuts off with no ill effect to my battery. I have had problems with the relays I chose to use originally. What I can tell you is this. You need a relay with a silver contact. Not copper! The copper ones carbon up quickly and then when the fan is required it doesn't come on. This was how I found out my high speed circuit works. 
Anyway, when the relays are working, the high speed has never been needed. Over the course of this past summers IDI Weekend, I added two LED's that inform me the status of the fan. What I discovered by adding these, was that the fans spin from road air, even when they are not called upon, and generate enough electricity to light my low speed LED. So this is kind of neat, because I can see the LED start to glow as the fan spins up. It never gets as bright as if the fan was actually commanded to come on, but it does confirm that there is good air moving under the hood. I used to have a lot of cool pictures of how I did this fan setup, and how the project went. But sadly, Webshots killed all our pics and I lost them all. Pretty much wrecked a lot of our tech articles. http://www.oilburners.net/forums/showthread.php?23946-Electric-Fan-Conversion-for-the-wide-rad
Anyway, when the relays are working, the high speed has never been needed. Over the course of this past summers IDI Weekend, I added two LED's that inform me the status of the fan. What I discovered by adding these, was that the fans spin from road air, even when they are not called upon, and generate enough electricity to light my low speed LED. So this is kind of neat, because I can see the LED start to glow as the fan spins up. It never gets as bright as if the fan was actually commanded to come on, but it does confirm that there is good air moving under the hood. I used to have a lot of cool pictures of how I did this fan setup, and how the project went. But sadly, Webshots killed all our pics and I lost them all. Pretty much wrecked a lot of our tech articles. http://www.oilburners.net/forums/showthread.php?23946-Electric-Fan-Conversion-for-the-wide-radDccontrols fk-85 that I have uses a nice sealed unit temp sensor that installs in the fins of the radiator. I have mine in the bottom, some people put them in the top for faster response. The wiring is very simple as well. Power, ground, then out to the fans. You have an LED that goes from green to red based on fan speed. And you can wire in to the a/c system to make sure the fans are running while the air is on. This was the main reason I wanted this controller.
System works very well, I just wish I could find a fan that moves more air over the radiator when they are on.
System works very well, I just wish I could find a fan that moves more air over the radiator when they are on.
jaluhn83
Full Access Member
I would go for about a 205-210 on and 190-195 or so off. The thermostat is fully open at 192, but starts to open earlier. I see normal cruise temps around 185. You do want to make sure your low temp on the switch is higher than normal running temp so the fans actually shut off.
I prefer to keep temps low - yes, 220-230 is okay for these trucks, but I fell more comfortable keeping in the 200-210 range under load, which means having the fan on at ~200. With my electric clutch setup I mainly use a manual switch and just kick it on before hitting a hill - works well so far.
You could also weld/braze a fitting into your radiator top tank and use that. Under load the top tank temp follows pretty close to the engine coolant temp. (I've tested this on my rig)
I prefer to keep temps low - yes, 220-230 is okay for these trucks, but I fell more comfortable keeping in the 200-210 range under load, which means having the fan on at ~200. With my electric clutch setup I mainly use a manual switch and just kick it on before hitting a hill - works well so far.
You could also weld/braze a fitting into your radiator top tank and use that. Under load the top tank temp follows pretty close to the engine coolant temp. (I've tested this on my rig)
