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For the last few weeks when I start driving in the morning the engine fan (747 jumbo jet fan) is really loud when I first take off for about 30 seconds or a minute. The fan will be loud through first and second gears, and then will go back to normal in 3rd gear. Sometimes it'll go back to normal while still in 2nd gear. This only happens when the engine is cold.

I'm not sure exactly how that fan clutch works, but it seems like when it is cold and there is resistance, the fan is locked in, and then as things loosen up it goes off. Makes me think my fan clutch might be slowly failing???
 

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Sounds like it is working correctly. Over night the fluid inside drains down into the area that locks the fan clutch up. As you first start driving,it takes a few minutes for the fluid to get "pumped" out of the lockup area inside the housing. We should all hear that roar each morning.

As the spring in the front of the clutch gets hot from hot air, it twists a valve inside the clutch, and the thick fluid is "pumped" into the lock up area inside the clutch. And that locks the fan up. Once the air cools down some, and the spring twists back the other way, it closes off the valve inside and fluid is no longer pumped around inside, and the clutch spins free.

A bad clutch would be evident by not hearing that roar in the morning. Also, if you grab the fan blades (Engine OFF) and you can wiggle it back and forth, it means it is time to replace it. I personally have been through 2 radiator fans and clutches because the plastic fans get out of balance over time, thus causing undue stress on the clutch, and ultimately, the water pump bearing goes bad because the constant wobble of the bad plastic fan wears it out. You must visually watch the plastic fan when the engine is on. An out of balance fan will be obvious.
 

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Ya perfectly normal. Ford describes it as "morning sickness"
 

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Funny, mine does not do that at all. The only time it comes o is when I am pulling a grade and the engine temps rise to the point that it need additional cooling, the clutch engages, cools the engine, and then disengages.
 

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Anybody hear the fan engage and run 2 different speeds? It's like it cycles between 2 speeds and then unlocks after a while. The pitch is different between the 2 speeds and goes away when it unlocks.
 

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Anybody hear the fan engage and run 2 different speeds? It's like it cycles between 2 speeds and then unlocks after a while. The pitch is different between the 2 speeds and goes away when it unlocks.
What a coincidence. I got on here for this very reason. 1999.5 F350 DRW 7.3 Powerstroke. I just installed a new fan clutch, then embarked on a Phoenix/Des Moines road trip. I was not pulling anything, just me and the kids. Everything seemed fine initially. Then, around the latter third of the trip (Kansas, Nebraska, Iowa…flat), the fan took on an unusual characteristic. When actuated, the fan cycled between the two speeds every couple of seconds the entire time—high/low/high/low/high/low, etc., until it would cool enough to de-actuate. Ambient temperatures were in the 70s and 80s and I was traveling on the interstate at a consistent 80 to 85 mph. This had never happened before. Seems to me this is not right and that the new Hayden fan clutch is faulty. Input?
 

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I noticed my fan clutch doing exactly what you described sometime earlier this year. My clutch would not lock up when hot though... I replaced it last week and the new one does the exact same thing only for a longer period in the morning. The difference is, the new one also locks up when hot. I heard it at a red light the other day and when I stopped at an interstate rest area after 3+ hours or 70mph driving.

So double check its function when hot before replacing it..
 

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Good input guys, but I guess I'm still not sure if I'm hearing the beginning of a failure or if it's just normal...is there an actual test to be done?
 
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