Radiator fan run time????

[rj35pj]

Since I am replacing my radiator that is leaking I'm taking another look at my fan and how much it runs. Once the engine is at operating temperature (180) my fan runs constantly even when out on the highway. My engine temp has been great, consistantly around 180 degrees on the open road and in town. My question is why have it running when I'm on the highway.
Should I go to a 160 stat or go to a higher fan sensor switch say 190 or 210? Or should I leave well enough alone and let the fan run.....

Any input apppreciated.
Thanks,
Bob
PS i'm running a Ford 306 from Ford Racing, 4 barrel carb, 340hp nothing too fancy....

[Bob Cowan]

You should have the fan come on at about 15* above your thermostat opening point. And then have it turn off about 4-5* below that.

As for highway speeds, you could put a switch in the circuit so you can turn it off. But, if you're like me, you'll forget to turn it back on until it over heats.

I have a thermostat control for the fan. I also have it controlled by RPM. When RPM's are below 2,000 the fan is on.

[CHAZC5ZX]

I guess this could depend on where you installed your fan control sending unit. Mine is in the radiator fin's just below the water hose and seldom comes on above 30 MPH.
I have seen people put it in the intake manifold which just never made sense to me.
Chaz....

[rj35pj]

I guess this could depend on where you installed your fan control sending unit. Mine is in the radiator fin's just below the water hose and seldom comes on above 30 MPH.
I have seen people put it in the intake manifold which just never made sense to me.
Chaz....

Chaz, mine is in the intake manifold which you are right doesn't make sense. What kind of a sensor are you using in your radiator fins.......where did you get it. Thanks.

[skullandbones]

Chaz, mine is in the intake manifold which you are right doesn't make sense. What kind of a sensor are you using in your radiator fins.......where did you get it. Thanks.

1
X2 on that comment. I, also, wonder about the sensor in the intake manifold but not having the expertise or experience to set out on my own design had to follow instructions for my application. The end result is three temp sensors (1 computer, 2 water temp gauge, 3 fan sensor). I have seen a few radiator mounted sensors at rod runs and shows but still don't how well they work or how you adjust them to fit your application. When my two fans are running, it sounds like I have a supercharger under the hood. I'm sure it could be controlled in a more efficient way. Thanks, WEK.

[CraigS]

Bob, your fan should go off when you get moving. I have been using an adjustable regulator on mine. I started w/ one that had the probe in the radiator which lasted about 5 years. When it died I thought I might get a more accurate system w/ one that has a sensor in the water passage in the intake manifold. I got this from Summit
Derale Performance High-Amperage Adjustable Fan Controllers 16779
It's about $85 and it worked right out of the box on my 180 degree normal temp engine. I have made maybe three small adjustments since. If you look through Summit you can spend double that cost and can get features like bringing the fan up to speed over maybe 10-20 seconds to reduce the amp load shock to the battery/charging system. Some can be wired to have the fan run for "X" minutes after you turn off the engine. neat ideas but I didn't think I needed them.

[CHAZC5ZX]

My controller is A Hayden 3647 I got on Amazon I think under $30 bucks. I used A not to sharp pencil to wallow out A hole in the fins between the cooling tubes. I ran the sensor through A piece of 3/8 steel fuel line to protect the wires then bent it to shape and mounted it to the side shroud. I also put A piece of shrink wrap on the bulb and first couple of inches or wire. The control box mounts on the back or the shroud and has A screw to adjust the temp range.
Chaz...

[Stengun]

Howdy,

If you have a 180' thermostat you need your fan to turn on at 190' to 195' and off at 180'.

Fan sensor in the radiator of the intake manifold?

Gee, are you concerned with the temp of your engine or your radiator?

Me? I'm concerned with the temp of my engine, not the radiator.

I have 3 temp sensors: #1: ECU; #2: temp gauge; #3 cooling fan.

Paul

[CHAZC5ZX]

Gee in this case I am more concerned with the temp of the radiator.
the engine thermostat's job is to maintain A constant temp IE 180*
The radiator's job is to keep A supply of "cooler" water available to keep that constant temp....Right

[Olli]

Does anyone know what the 'turn-on' temp is with the FFR supplied thermostatic fan switch? The one I got doesn't have any markings on it and it was just in a plain unmarked plastic bag.


Olli