I have a 08 SuperDuty 6.4 PSD, and last night when I went to start it up to run and errand it started really strong, and when I backed out and pulled away I noticed a loud noise coming from the hood, it almost sounded like the fan was moving really fast, and it would get louder and "faster" as the RPM's went up. But after a couple minutes of driving it in my neighborhood it went away and drove normal. And over the last few days I did notice that it started strong, but then it wouldn't do it anymore, and my temp gauges were down until the engine was driving around and then they would go up and tell me the temp. I suspected that the suspected high fan speed was to help the engine warm up, but IDK. I know some stuff about engines but I'm no mechanic, and I'm going to a scout camp in a couple of days and would like to know what is wrong before I go. Thanks!

 

My 09 does the same thing. Don't think anything is wrong just does that when it's cold.

 

Not a thing is wrong. I have the same truck, job 1 and it may do it when it 30 degrees here in Texas. Its just the fan clutch, be glad it works! Mine is doing it also, as its 104 everyday when I start it to go home from work.

 

Normal operation. My job 3 has done that since new as well.

 

Yeah, I read the engine supplement that came with the truck, and I found that it was the fan clutch just as you guys said. I live in Utah so we have a fluctuation of temperatures everyday it's 90 degrees now and at night we drop to 70 so we see temp changes very often. But anyway she's running like a charm and I'm taking it to the truck doctor tomorrow morning for a check-up so it will be just fine.

 

You can have them test the fan to ensure it's proper operation.

When towing heavy it will come on full blast and sound like an airplane.

That happens when I reach about 220F water temps.

 

Just watch for it to start cycling every few seconds when you start it, had that happen and the clutch was bad.

 

I did have a "rumble" last winter. You could only hear it when you shut down the truck. Took it in and it turned out to be the fan clutch. It was something as the fan was spinning down, the tech did not like the sound so they changed the clutch. No noise, now. It never failed me though. As stated above, let the truck doctor know and have them check it. But money is that you are A ok!

 

Sounds normal in hot wx.

 

I have the same job 1 truck and it worried me at first but after reading multiple posts on this site and others it is a normal event. For me it doesn't happen all the time, 1 - 3 times a week maybe, and it always goes away after a few minutes of driving. Like a poster wrote earlier, if it starts to do it every few minutes or more, there might be a problem and should be looked at. this was a good informative thread.