I’ve noticed this sound before but just recently made a trip through the <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1lace><st1:PlaceName>Smokey</st1:PlaceName><st1:PlaceType>Mountains</st1:PlaceType></st1lace> towing and wanted to get professional opinions on it. <?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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When towing up a grade with steady accelerator pressure and solid boost (25psi or so) I hear this sound that starts like a loud fan and then gets a high pitch whistle? I'm thinking it is the torque converter locking in and out as it will cycle? Do not notice any significant changes in RPM's, temp's or boost just wondering if this is normal? Gets annoying as it will cycle in and out and sometimes will stay in even after the grade levels out and reducing accelerator will not stop it? Even accelerator pressure once the grade levels out will eventually stop it. <o></o>
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My truck is a 2005 6.0 crew cad 4X4 dually with <st1:time Hour="16" Minute="11">4:11</st1:time> rear and stock other than Cat Back Duals. No aftermarket tune but recently had the newest Ford tune installed. Seems to have lost a little power since the tune? <o></o>
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I considered taking it to the dealer but where I live there is no hills and can not duplicate the problem. Any information would be appreciated. Thanks.<o></o>

 

maybe the turbo are the fan because it has a electric fan that is energized by a relay

 

Cooling fan is doing it's job cycling on and off.

 

It seems loud for a fan but makes sense? Never comes on when not under load even in the hottest days? Only on steep grades towing heavy loads? I guess it's OK just concerned it may be a transmission problem.

 

I get that sound in the mountains too. It was disconcerting, but it sounded like, and I thought it was the radiator fan turning on and off.

 

The first time you hear the cooling fan it does seem louder than you would expect. However, I wouldnt' describe the sound as a "high pitched whistle".

 

More like your Mom when she screams for you to get out of bed for school!!

 

I get the same thing on my '06 6.0 Super Crew F250 when I'm pulling my camper and only when I'm pulling camper. I'm sure it's the radiator fan. It is sorta odd that it changes RPM so much, sometimes it's fast, sometimes it's slow but, I'm sure that's what it is.

 

Thanks for the reply's...That is one loud fan! Not sure what the whistle is but probably harmonics from the fan. I feel better now

 

I've also got the high pitched whistle - posted about it two years ago on this forum. If you listen closely, you'll hear the fan clutch slow down when the whistle starts. It does not matter whether you have the A/C on or off. I've discovered that if I slow down about 10 mph on a hill, the coolant temps will drop and the noise will go away. Best description of the noise is that it sounds like a "tea kettle".

It's something slipping in the fan belt pulley system. I've had the fan clutch replaced and it did not help. Another member replaced the idler pulley with no improvement. Another said his dealer service department went after all the pulleys with some fine grade sandpaper to roughen them up and that seemed to help. Another poster said he had a Goodyear Gatorback belt installed and that solved the problem.

Ford had the same problem with the early 7.3L engines and issued a TSB. It said that the rubber in the belt was "the wrong composition" and they changed the belts out.

 

I was thinking pully too, but I will go ahead and replace the belt with the Goodyear one and check the pullies while I'm at it I am also going to jump the fan to operate it while truck is off to confirm sounds while hood is open. If its a belt noise a little spray of water may identify it.

Thanks for your service! American Armed Forces Rock!!!!

 

My fan on my 06 would cycle on and off at 4 second intervals and made a loud "whirring" noise. It only did it going up a grade. There was never any sign off overheating. I took it to the dealer Tues. and picked it up today with a new fan clutch and EGR valve. Haven't given it a test yet. The Tech said the belts are 100,000 mile belts and that's one thing the haven't had any problem with. I had them replace it anyway at 44000 miles. $119 for the belt only no labor WOW.

 

If you can live with that occassional sound from the fan when your pulling grades in hot temperatures then why change belts etc? Whatever makes the sound isn't hurting anything is it. Isn't It is just telling us that the fan is on the job and working.

 

A high-pitched whistle, tea-kettle sound, or "air across a coke bottle" sound are all desciptions that fit leaking head gasket(s).

The fan coming on is not a problem necessarily. If it comes on more and more frequently, it can mean inadequate cooling OR leaking head gaskets OR (less likely) leaking EGR cooler.

When the 6.0L trucks coolant system is working as designed, it is rare that the fan needs to operate. Usually it is only in hot weather conditions AND while towing a heavy load. Even then, because the fan moves so much air, that it will cycle on and off.

Look for white residue around the degass bottle and loss of coolant level.

With the whistling, you could also have a bad degass bottle cap. Ford came out w/ a new one - about a year or so back.

 

The sounds I am hearing is definately something cycling on an off it could not be a head gasket or the coolant burping...