I have had a really loud high pitch whine the last couple of times I towed my 3 horse LQ trailer. It is usually while going uphill, fully loaded. We can hear a fan kick in and run for a while, but after that there is a loud whine or almost like a buzzing sound. Anyone have this experience before? Any ideas? It is at the dealer right now, but of course they can't replicate it.

 

Is your F350 a 6.0? 03-06? Earlier 7.3? Need a place to start If it is a 6.0, there's a TSB (05-21-9) in regards to a Whine/Whisltle from the Turbo area, along with a diagnostic proceedure to isolate the noise.. Any additional info. might help narrow the cause/s..

.........................HP..................

 

Hi there, thanks for your help.
Let's see. It is a 2004 F-350 6.0 turbo diesel engine 4WD.
It only has made the noise when towing uphill fully loaded with all 3 horses. As I said earlier, I hear some kind of fan kick in for a while, and then it makes that load whine/buzz sound. If I let my foot off of the accelerator it will subside, but it starts again when I accelerate.
Do I ask the dealer to refer to the TSB 5-21-9 that you mentioned?

 

The Vistronic Fan (the cooling fan you hear) will make 'alot 'of noise when it cycles.. Or can..

The cooling fans 'electronic clutch' is controlled by the PCM (computer). The PCM monitors the engine 'oil temperature', engine 'coolant temperature' ect. and it sends a duty cycle/command to the fan clutch to run for needed cooling for the conditions met . A/C request/usage will also play a part in the duty cycle of the cooling fan as well..

If you feel that this noise isn't part of the cooling fans 'roar', then if you took it to a good tech/dealer, they'll know to look for current TSB's SSM's (Technical Service Bulletins/Special Service Messages ect.) in regards to your truck.. If they lean towards just the fan, and you want them to have a good look at it for you, you might want to give them the TSB number and ask them to check it for you.. Sometimes shop conditions are a bit harder to duplicate for issues than real life driveability concerns as with high boost pressures/turbo ect. as you state in your towing capacity/grades, that might be harder for them to diagnose..

..................HP................

 

Any running/driveabilty issues, like bucking/jerking that accompany the noise?