Electric Cooling Fan, Where does the Thermostat

[franklin2]

Well, I guess it's best if the sensor goes on the rad. Maybe I will get lucky and there will be a pipe thread location for it. Won't know til I get it.

Just curious. Does fluid go in the bottom of a rad to follow convection?

Thanks

Most cooling systems I have seen, the waterpump sucks on the bottom hose of the radiator, pushes the coolant through the engine, and it comes out of the engine through the top radiator hose and back into the radiator.

The instructions on the fan switch I bought said to put it in the coolant like I did, or however you can do it. Some of them do have sensors that clip into the fins of the radiator. If that is what the instructions say, I would follow them as close as I could.

 

[Raspy]

Not true if the sensor temp is set correctly, which it is supposed to be. For example, the engine thermostat let's say is 190F. The fan thermostat can be set at 220F. The engine will warm up to 190F, the thermostat will open, and water will flow through the radiator. Depending on conditions, the radiator starts doing it's job and the fan may not come on at all. If there is a large load or it's a very hot day, the radiator and the coolant will get to 220F and that will kick the fan on. On this unit, the fan will most likely stay on till 205 to 210 when it will cut off.

Yeah, that makes sense, but the stat could also be set at 220 and be on the radiator. It's just a more direct way of measuring the temp that the fan is directly controlling. I'm not so sure about the sensor in the coolant in the manner described where the capillary goes in under the radiator hose. Then the bulb has a chance of not being supported well. Of course I don't know what this particular bulb looks like or how far in it will be pushed, but hanging out in an active water stream in a horizontal pipe, for instance, seems like a failure point. I'd just put it on the radiator and set it to only run when the radiator was hot.

 

[Raspy]

Well, I guess it's best if the sensor goes on the rad. Maybe I will get lucky and there will be a pipe thread location for it. Won't know til I get it.

Just curious. Does fluid go in the bottom of a rad to follow convection?

Thanks

No. Hot at the top. But most radiators these days are cross flow. Even if it did rely on convection, it would go in at the top so that as it cooled it would migrate down. Then the engine heats it and it migrates up. Pumping it has much more force than convection. After the engine is shut off, the convection can still work though, as the water in the rad cools and circulates back to the engine until the thermostat closes.