I think my fan roar is inherent with the fan clutch. The thing engages with the temp (by the input of power from the computer) and engages until the hydraulic fluid in the clutch pumps out, just like my two gassers did. I think it is probably the same on all CTDs but the fan for the 2003 might just be a little more efficient and the CTD is certainly quieter therefore you hear it better. My 1990 something F--D gasser made the same noise till I accelerated a little and off it went, same as my Ch--y gasser and my F--D diesel. They all respond when cold with a locked up fan till the fan clutch stabilizes and disconnects. I have never ripped a fan clutch apart but I believe they have fluid in there that drives it till it pumps the fluid out of the reservoir and then it shuts off. JMHO

 

Ken , I made a similar post some months ago. It is totally normal, unsubscribe from the thread and call it a day..

At work we have 2 dodge gas vans that do it, my '97 tahoe did it, and my truck does it. My MB diesel also does. The truck sounds like a big rig pulling off with the fan and engine going

Someone did explain the technical reason of why it went on when I had asked, maybe do a search if you are curious. I know I wasn't totally convinced regardless of all the people telling me it was normal until I read the tech reasons. Regardless, try to trust us, it's normal

 

Mine pretty much stays on under 2000 rpm. That's with the A/C on. With the A/C off it hardly ever comes on.

 

I dont recall ever hearing mine with the a/c off.

 

my fan has roared since it was new 03 4x4 diesel i have 42000 miles on it.

 

I keep seeing references to other vehicles that do the same thing......it aint the same folks! Go back and reread....the clutch fan on the new CTD is "PCM CONTROLLED", crawl under your truck and you'll see the wiring harness running to the front of the fan. There is a fan speed sensor as an input to the ECM (cummins controller). The ECM uses input from the speed sensor to control the viscous fan drive. You can watch on the DRB scan tool and see the changes the ECM requests as you turn on the a/c or sit at an idle in the heat. I'll try to do some digging and see what other conditions would make the fan engage.

 

If you don't have the AC or Defroster or Recirculate mode on then the fan should not come on except when it's hotter than dog shizzle out there. If it does then you most definatley have a problem. Take it oto the dealer and hve them put the computer on it and see what's going on with it.

 

My fan roars and blows a lot of air while it's doing it. Sometimes I'm afraid my truck is going to take off.

Where it's bad is driving through a crowd of people in dusty conditions while the fan is roaring. At least in my case....even crawling along in first gear....that fan kicks up a LOT of dust and it kind of ticks people off.

As most have said though.....it's normal.

 

Mine only comes on when the A/C is on at stoplights and turns off at about 25mph. Happens 50 deg. F and up. Also comes on when I first drive away in the morning for the first 1/8 mile.

 

Fan ROAR is Good Means it is working

 

fan speed is 1.2:1 of engine speed until you get above 2600rpm engine speed, then the fan speed starts to drop off to about 2700 max

 

Mine has the fan roar as well. It doesn't bother me i would rather here and know its working than to be wondering if it's working at all.

 

I think the fan roar is normal. I purchased my truck in early "03" its first recall was to check the fan tightness on the water pump. at about 5,000 mi when shutting it down I heard the normal belt chirp from the instant stop. A few seconds later I hear a clunk!.......I didn't think much of it till I got back in and went for a drive.....kept hearing an odd sound.... lifted the hood and had a look.... the fan wasn't hooked to the water pump anymore. No damage to anything except the fan clutch threads when it blew back against the water pump while I was driving(the noise I heard). The Dealer pulled a new fan off a new truck and I was on the road ! We compared the resistance to turn the clutch on the old and new....the bad one seemed to be much tighter! If it is locked up when you shut the engine down and all comes to an instant stop the fan wants to unscrew itself from the water pump! The good news is it is pretty much stopped and just falls into the shroud and no damage occures......at least in my case!

 

Next time it does it to you, punch on the throttle stiffly.... just a snap.. see if the xmission upshifts and changes things for you. I have it.. But I've had them do a "reboot" or something.. flash the chip, whatever they do... and it took care of it for a while. I think the xmission loses it's mind and doesn't know where it is. I noticed the rpm was up when this was happening and thought it was fan roar too... turned out it's rpm. Needs to upshift. Play with that for a while and see if it doesn't change things. Then have your dealer reflash the chip. They said they could tell it needed it... for what that's worth. Mine's doing it again so I will take it back eventually. I attribute it to towing, or working it, but don't have anything to substantiate that. Good luck

 

I've never heard my fan that I know of, including hauling 3400 lbs of rock and hauling about 800 lbs of firewood around recently. Of course, my ears ring some, and my Chevy used to sound like a jet taking off when the fan kicked in, I may just be missing it.