Hi,

My rig is an 01 Excursion 7.3 diesel--103K mi, pulling a 5K lb travel trailer. Lately, I have been having a high pitched squeal when the fan engages. Sounds almost like a belt squeal. But--I have replaced the serp belt and the tensioner, as well as cleaned all the pulleys with lacquer thinner. I am starting to think it is the fan clutch--seems to happen just at engagement. Once engaged, you can also hear the fan speeding up and slowing down, rather erratically. Has anyone else had this experience? Other than that, rig seems to be performing just fine.

Thanks,
lew b.

 

Lew- I am having the same problem - Mine is only under load when towing & hot outside temps. - There is currently a thread about this if you scroll down it may help- Let us know how it comes out. Thread title is "Occasional Squeal while towing "

 

Fan Clutch? Squeal

Update:

I realize this is a bit late--I did replace the fan clutch in 2013--squealing kept happening when fan would engage at high temps and loads when towing on hot days. It sounded like the belt and it always happened when the fan kicked in. This summer, I released the belt tension and used a very aggressive wire wheel on my cordless drill to roughen the water pump pulley with a cross pattern--thus giving more "bite" for the belt to grip. That solved the problem! All summer long I did NOT have the squealing any more. I suppose replacing the pulley would also work. I think they become glazed, since the water pump pulley runs on the back (smooth) side of the belt.

Lew B.
2001 Excursion 7.3 PS.

 

Lew, it is also possible that one of the pump bearings are getting dry. When you roughened up the pump pulley that could possible enable the water pump to run at belt speed instead of slipping. Just something to mull over. How many miles on that water pump? Larry