Electric fan control switch

Okiedokie · January 28, 2008, 10:25:48 AM

I have decided to put a shrouded electric fan on my 53 F100, CCI. I am trying to decide about a control switch. The one on my 46 turns the fan on about 200 degrees and off at about 185 I believe. I notice that now a company by the name of Maradyne makes a switch that has the same on/off temp. 185 or 195. This seems to make sense to me. It would seem to eliminate the anxious wait to see if the fan is going to kick on and the up and down of temp in high temp/slow traffic conditions. What do you guys think? Joe

phat rat · January 28, 2008, 10:55:31 AM

You can also buy an adjustable switch. I have mine set to go on at 200 degrees. This temp is read by a probe that actually goes into the radiator. I had an extra bung put into the bottom of the radiator for just that purpose.

enjenjo · January 28, 2008, 11:06:55 AM

The problem I see with having the on/off temp the same, is the fan starts and stops a lot.

slocrow · January 28, 2008, 11:14:39 AM

Quote from: "enjenjo"the fan starts and stops a lot.

We have a winner........................ :b-d:

Dave · January 28, 2008, 02:43:41 PM

I run the kind that are adjustable and go in the radiator lower tank or in the fins. Never noticed it being a problem and its set for one setting although its adjustable..
Dave

Leon · January 28, 2008, 03:20:54 PM

I have the Dakota Digital control that uses the same sensor as the gauge. It is adjustable for both turn on and turn off points, and can run single, two speed, and dual fans with individual settings.

Okiedokie · January 28, 2008, 05:03:40 PM

SO----phat rat and jusjunk are doing the same as having a switch set at one temp on and off, isn't that correct? If yours are adjustable why not set them at different on and off temps? I know that the norm on set [non-adjustable] switch's is two different temps, I am just trying to figure out why. Joe

phat46 · January 28, 2008, 05:25:13 PM

I use a toggle switch under the dash, turn it on when i want, off when i want.......as long as i remember

model a vette · January 28, 2008, 05:49:33 PM

I used a switch that was OEM on one of the Chrysler minivans. It was designed to be mounted in the lower radiator tank. I think it is 200 on - 185 off. It has two terminals so you have to ground one terminal and run the other to ground terminal on the fan relay.

rumrumm · January 29, 2008, 09:32:57 AM

I used this unit from Centech and highly recommend it. You can set the point where the fan comes on. Easy installation.

www.centechwire.com/catalog/cooling/fc2p.shtml

EMSjunkie · January 29, 2008, 01:04:18 PM

Quote from: "rumrumm"I used this unit from Centech and highly recommend it. You can set the point where the fan comes on. Easy installation.

www.centechwire.com/catalog/cooling/fc2p.shtml

I had on of those on my coupe, I really liked it.
but it got fried in August, and I haven't replaced it yet.

no fault of the controller that it fried. but that a story for another time :oops:

Vance

Okiedokie · January 29, 2008, 03:52:51 PM

Ok, so I ordered a "on at 190, off at 175" switch that screws in head or intake. I still am unsure why this is better, but I did it. It is what I have on my 46 although I am questioning the range on that one and may change it. I will change the thermostat on the motor in my truck to 185 if that is not what I put in it originally. I see that most of the rod shops are selling either these temp switch's like I bought, or the adjustable ones that you can set to turn on at what temp you want, or the Dakota and Centech that you adjust on and off [which makes more sense to me than only on]. I see that most now offer the screw in the head/intake that are one temp on and off in various degrees. Since I am now curious about the temp range of the one in my 46 I think that I may get one that is same on/off temp and match it to thermostat and see what happens. Thanks for all your input on this. Wish I could say I totally understand it, but at least it has my feeble brain churning. Joe

1FATGMC · January 29, 2008, 04:03:40 PM

Quote from: "Joe Gaddy"Ok, so I ordered a "on at 190, off at 175" switch that screws in head or intake.

I have a question. If you are using a 185 thermostat and it goes to 190 and the fan comes on. It drops below 190, but it won't turn off until it gets to 175. At 185 the thermostat closes and cycles off and on keeping it near 185. So when does the fan ever turn off? After you park??

We just put a sbc in Shaun's Z in the background and just got a fan control in for it that you can determine the on off points.

We'll see if it works if we ever get to summer again.

c ya,

Sum

enjenjo · January 29, 2008, 04:27:23 PM

Ok, the reason you don't want it to turn on and off at the same temperature.

The toughest part of an electric motors life is the start up. It draws more current, and loads the windings more. If the on/off temps are the same, as soon as it starts, drops the temp one degree, it shuts off. Almost imediately, the temp goes up, and it starts, the temp drops, and it shuts off. Over and over. Real hard on the fan motor.

I am not an advocate of having the fan come on too soon. Most cooling systems operate well into the 230 to 240 degree range. And the engine will be more efficient running at 200 to 210 degrees. So making the engine run colder than that, while possible, is not the best idea.

Running a colder thermostat, 160, or 180, makes no difference in the effectiveness of the cooling system, and will only marginally increase the time from good temperatures to overheating. This is particularly true of fuel injected engines.

brti · January 29, 2008, 04:48:16 PM

Now that we're on this subject I ahave a question.,,,,,, Which is the most reliable temp sensor? The ones in the head or manifold, the ones that go under a thermostat housing bolt, or the real nice looking ones that slip under the rad hose into the rad reservior?
Thanks for your input.