When I am towing my fifth wheel up a grade there is a fan that kicks off and on, . ( I think it is the trany fan), I could be wrong about that however. Anyway there is a fan that kicks on and off when the motor is under strain,at about 3000 rpm and climbing up a hill, there is a whistle inside the cab when the fan cycles off then the whistle goes away when the fan cycles back on. When I level back off and the fan stops cycling, the whistlle goes away. What on earth is this anoying whistle? On occasion the motor wants to run excessivley hot when climbing and towing. ANY SUGGESTIONS? Any one else with this same whistle?[8D]PLEASE HELP!!!

 

How heavy are you towing?

The ‘engine’ cooling fan is a Vistronic Drive Fan or (VDF) The cooling fan has an electronic clutch that is controlled by the PCM (computer). The PCM monitors engine oil temperature (EOT) and engine coolant temperature (ECT) and sends a duty cycle or ‘commands’ the fan clutch operation for adequate cooling when needed. Usually startles most if they’ve never heard it before.. It’s duty, or fan application is also A/C related for needed cooling. This is what your hearing or cycling when towing.. It can come on even when not towing depending on temps, and demands ect.. Although ‘high temps’ during towing aren’t normal and should be checked to avoid any engine issues from over temp conditions if they exist..

Below is a Technical Service Bulletin in regards to your concern.. But being that you state the whistle cycles with the fans operation, this may not apply, and could be a fan issue.. It should be checked for this condition, and any other Y pipe cracks, or exhaust leaks ect.. But they would most likely still be present even when 'not' towing if they were the cause, or you may even detect excessive diesel smell that might accompany the whistle sound when not under load.. Although high boost conditions may worsen the affects..

TSB 05-21-9
Whine Whistle Noise- 6.0
ISSUE:
Some 2003-2006 F-Super Duty, 2003-2005 Excursion and 2004-2006 E-Series built with the 6.0L diesel engine may exhibit a whine/whistle noise coming from the turbocharger area.
ACTION:
Refer to the following Service Procedure to isolate and repair the source of the noise.
SERVICE PROCEDURE
1. If a whine/whistle is present, use WDS datalogger active command function to open the EGR valve, or unplug the variable geometry turbo (VGT) control solenoid. This will reduce the exhaust back pressure.
a. If the whine/whistle noise is still present continue with normal diagnostics.
b. If the whine/whistle noise is not present continue with this TSB.
2. Use one of the following to verify the source of whine/whistle noise at the EGR Cooler connection.
a. Listening device (vacuum hose, etc).
b. Smoke from a smoke machine (Rotunda 218-00001 or equivelent) introduced into the exhaust pressure (EP) sensor tube.
3. Replace the EGR cooler to Y-pipe gasket following Workshop Manual, Section 309-00 and tighten ERG Cooler V-clamp nut to 53 lb-in (6 N-m), or replace the EGR cooler to intake manifold gasket following Workshop Manual, Section 303-08.

 

About 14000/15000 lbs and the whistle seems to be coming from inside the cab not outside, the strange part to me is it only happens when the fan is between cycles of - off and on, it doesen't happen when the fan is done cycling[>:] its a real high pitch whistle, and I mean it litterally is inside the cab. I can hear it over the stereo....

 

Well,,,,

The reason I asked about your towing weight, is that these engines have an EGR cooler.. (Exhaust Gas Recirculation Valve).. If you were to be at very high ambient climates, towing 'heavy', steep grades ect. and at high boost/throttle angles, you would be 'pushing' a high volume, high temp, exhaust through the EGR valve as the engines coolant (part of the EGR cooler) is trying to cool the reburn exhaust before entering the valve.. Which will also try and heat the coolant in the process.. Which might explain the higher gauge reading that you see 'if' abnormal, which also ties in with the fan running.. Being that the fan 'is' cycling would lead me to believe that your in a 'safe' range, but with out a scan tool to monitor temps, or seeing the gauge would be just a guess..

I'm still thinking of 'why' the whistle would only be present when the fan has cycled off, unless it's drowned out by the fan roar, as a high boost condition 'should' cause the issue (per TSB) no matter what the fan is doing I would think..

The TSB is in regards to a test, or elimination of, a gasket failure leak, that’s in the 'up pipe' that goes from the right/passenger exhaust manifold on upwards to the EGR cooler clamp/inlet, up past the clamp/flange (gasket) to the Y pipe.. This ALSO happens to run 'directly behind' the engine from almost center of the firewall towards the right manifold.. ALL within about 1 1/2-2" of the center firewall area which 'may' be sounding like your dash area... You might take a look at the 'right' passenger side of the turbo and follow the pipe to the flange before the 'band clamp for the cooler.. Look to see if you see any soot blown away/out from the pipe or against the firewall..

I just can't think of anything that would 'whistle' that is under the dash.. Especially a high pitch one, which sounds more like a high pressure leak.. There are no other running or performance issues other than the whistle..Right?

Let me know..

 

Actually the truck runs incredibly well,fast and strong towing and not towing I have the edge programmer w/ the juice and I only usually tow on the # 2 setting which is the tow mode..I have also tried to tow in the #1 setting which is the mileage setting as well as the # 0 setting which is the stock setting and still I get the whistle. The highest I have ever set the programmer is #3 which is the drive setting and never when I have been towing. If you are familiar with this particular programmer it has two higher settings that I have never gone to. It also has an egt sensor and a monitor in the cab so I can monitor the exhaust temps and they never seem to go higher than the recommended temp 1200 degrees. to describe the whistle in detail its a high pitch but almost exactly like as if you put your lips together and blew a steady whistle, It's actually kind of freekish. The bummer about the whole thing is that I cant reproduce it for the dealer unless I hooked up the trailor, loaded it up grabbed a ford rep. and headed from vegas tword utah, and pretty sure thats not going to happen...
[]

 

I have a similar whistle problem... the way things fell apart

1. loud pop going down 5% grade in tow haul... this no power pulling next and remaining hills...turbo not as loud and low boost.. usually 33-35psi now only 25 max.... fuel consumption has increased from 13-14 mpg to 6-8 mpg

2. pulling long steep grades.... 3100- 3500 rpm, 25 # boost, 40-45mpg, high pitch whistle and fan cycles high, low, off in no set pattern, whistle goes away when reduced throttle or up shift... boost varies, even though throttle held steady, all guages normal range...

3. ABS light on, now doen shift from tow haul and no automatic trailer brakes, have to apply manually...

took to dealeralong route after second item... they told me nothing wrong and this is normal....
I have pulledmy 40' 5th wheel for 75000 miles andthis IS NOT NORMAL OPERATION... has always had good power andyou couldhear turbo spool up, which you can't now....

 

This might be a litle detour, but I had a whistle in my o4, 6.0 350 under moderate aceleration when it was warmed up. It seemed to be coolant de-gasing out the coolant resevoir cap. Fords fix is a new oil cooler and hose with a restrictor valve in it. I never had to add coolant, but it stunk when it happened. I replaced the cap, and that helped some, but the thing that almost stopped the degassing completely was the addition of a couple cans of Red Line Water Wetter. Don't know if it was the same whistle or not, probably not, but it might be worth a shot.