Is my fan supposed to be running all the time?

I've heard talk that the fan is only supposed to come on at a certain temp but mine is alway's on.

I've got a new fan clutch and water pump and it did this even before they were replaced.

It moves freely when the engine is off.

 

Mine doesn't come on til the engine's been runnin awhile

 

mine runs pretty much all the time too. as long as its not giving me any cooling problems im not worried.

 

Mine only runs when I first turn the car on. This happened after the fan clutch was replaced...cause the fan didn't work at all. lol.

My truck never gets hot enough in our -40 weather here in Canada, so I dunno if it turns on if it get hot. lol

Pete

 

If your fan isn't electric it will turn all the time because it doesn't have a choice. It should turn some all the time wether the clutch is engaged in it or not because of friction between the parts in it.

 

Miles is correct. It will always be turning, but the amount of drag depends on the temp of the air that comes through the radiator and passes over the fan clutch. At specific temps, the fluid inside the clutch basically solidifies, making it a directly driven fan, with it's speed being directly proportional to the engine rpms. As the temp cools, the fluid loses it's solidity, and the fan kinda freewheels with the engine, creating little, if any, drag.

 

Even with my fan clutch completely gone it would turn.... about maybe 50 RPM! LOL

An easy way to check it to do it with the truck completely cooled, preferably after sitting overnight. Start the truck and you should get the fan "roar" at first. Hitting the gas it will appear that the fan is turning just as quick as the engine.

After a couple minutes the "roar" should quiet. Let the truck warm to normal temp.

Then get someone to sit in the truck and watch the temp gauge and give it some gas, while you block the flow with cardboard or towels, blankets etc from the front. Leave the space in front of the clutch unobstructed. As the temp comes up the fan should engage more and the "roar" will come back up. Remove the radiator/condenser block and the temp should come back down.

It's easier to do this with two people, to make sure you don't let the temp come up too high. Popping the grill off makes blocking the flow much easier.


On my truck when the clutch went, it went quick. Strangely it seemed to have some resistance when turned, but if you kept turning it maybe 20-25 times, it turned into nothing more than a bearing.

With the new clutch in place I notice the sound more.... maybe it did give me a clue, but I just didn't notice the gradual change in sound. Either way it's easy to test and I found out that the system is strong enough to mask problems. Read my post on "heat swings" if you want to see what I went through.