noticed a couple days ago my fan doesn't roar anymore. spins freely when cold with little resistance and when shut off after warm it doesn't keep spinning almost stops instantly when the motor does.
anything to worry about? its been kinda cold here around 20 during the days

 

My fan is loud when it starts up, but gets quiet quickly. Once it's all warmed up, you can even stop it with a gloved hand...ask me how I know...

 

scott1346, Your clutch is bad. With a stone cold engine, there should be resistance if you try to turn the fan by hand. If you shut the engine off and check it immediately after driving at operating temp, it should turn fairly easily. If/when the engine overheats, (no coolant in the radiator) there is no hot airflow across the thermostatic coil in the clutch to keep the fan disengaged. Which causes the clutch to lock up in an attempt to bring more airflow across the engine to cool it.

racsan, you're right about the old Ford's not having a clutch. They used what's called a "flex fan" cuz they were too cheap to put a clutch on it The blades on the flex fan were very thin, and as the water pump rpm increased, the blades would flatten out and quiet down. The problem was when they flattened out, it created an air dam behind the radiator and restricted the airflow through the radiator, kinda defeats the purpose of the fan Back in the late 70's, Ford had a recall on the flex fans. With all of the flexing back and forth, the blades would crack and fly off the hub. I remember seeing one come in with a slice in the hood. Looked like somebody took a knife and cut it, had a blade missing too Could be deadly if someone was in the wrong place at the wrong time. Better idea? No, bad idea.

The longer the clutch stays engaged cold, the quicker it will engage when you need it. It all has to do with the temperature that the thermostatic coil is set for.

 

It" really no big deal, if working properly they will disengage quickly.

 

I worked in a heavy truck shop about 20yrs ago
they a fleet of Ford tractors with Cat engines
We had a blade and part of the hub break away and go thew the hood of the truck
After inspecting the rest of the fleet , they all had cracked hubs
Ford said there was no issue but had fan assemblies in stock

 

kinda confused with this clutch. . . it still locks when hot but free wheels when cold it just doesnt have that roar in the morning. its gotta be bad though cause i just pulled it apart and it will spin with resistance then it frees up after half a rotation or so to no resistance and has this weird noise. yesterday i did the test where you watch the blades after you turn the car off if they keep spinning there bad mine did NOT keep spinning so in that sense its not bad its still locking up when hot and releasing when cool? i think that's how it works

 

what clutch should i replace it with??

 

scottl1346, If you do any towing at all, you might want to consider the severe duty one. Imperial #215158. Advance, O'Reilly and AZ all have them for just under $60. Need a 36mm open end wrench to replace it.

 

all fixed thanks captain hook. sorry for the thread highjack but hope it helps someone