radiator mounted fan control sensor

[stacked33]

Does anyone know at what temp the fan should turn on using the supplied radiator mounted sensor/switch? I ran the engine temp to 200+ and the fan didn't come on. I tested for ground and power and had both. Either it is not working or it is pretty high. Stacked33

[stack]

It may be around 212. Or the temp at the radiator was cooler so it didn't open

stack

[wallace18]

My sensor from FFR never worked. I bought a 185 unit from Ron Francis.

[stacked33]

I found that the water was not moving fast enough through the system so the water was cooling down before it got to the sensor. Even when the water coming out of the engine was over 200 the water at the bottom of the radiator was only about 140 (measured). I had bought a pulley setup that was designed for high RPM and I don't think it was moving enough at idle so I changed the crankshaft pulley to a larger one. I also replaced the supplied switch with a 185 degree from Summit.

[CHOTIS BILL]

In most cases the temp at the bottom of the radiator is a lot less than at the engine because the water has been cooled down by going through the radiator. The temp should be taken at the top of the radiator near the inlet or at the engine.

Bill Lomenick

[skullandbones]

If you have access to an infrared thermometer, take the temp of the intake near the water outlet to see if the water temp gauge is close. I don't know if the FFR sensor is adjustable but if it is not you should get one from Summit that can be adjusted. This will allow you to dial in the fans to where you have optimal on/off control. It may take a little tweaking to get it just right. I have a Summit fan system and the sensor is not adjustable but the fans cycle on and off great and you can see the movement of the temp gauge as the fans do their cycling. BTW, I read a book by Charles O. Probst about the small block fords and in that book he says the sbf runs best at 195 degrees. I thought that sounded high but he's the expert! Good luck, WEK.

[bbksv]

I second moving the sensor to the intake. With mine at the bottom of the radiator I was running 210+. I moved it to the intake and now I run 180..I know its a little cool but it works and I dont have to worry about it overheating.

[hdnik]

I put a fan override switch in for the same reason. Maybe a new unit up top somewhere isn't a bad idea.

[BrentM]

Mine has never come on, I have an override switch that I throw when the temp gauge got to 200° and the fan had not come on. with the fan on it runs at 190°. My sensor is located in the bottom of the radiator. Does anyone know what temp the FFR switch grounds at?

I was planing to take it out and put in in a pot of water to test it, but I just filled the radiator. I definitely need to change it just trying to figure out what to change it to.