Your engine will overheat and if the belt also drives the P/S pump you will loose your Power Steering making the vehicle extremely difficult to steer.
There is no Fan belt. There is a serpentine belt however. If this breaks do NOT run the car. This belt turns the water pump keeping your engine cool. You will have major issues if the engine overheats.
If the fan belt sticks or breaks, the most likely result is that the engine's cooling system will be compromised, leading to overheating. This can also affect other components driven by the belt, such as the alternator and power steering, resulting in loss of electrical power and steering assistance. Ultimately, continued operation under these conditions can cause severe engine damage. Regular maintenance and timely belt replacement are crucial to prevent such failures.
Take it to the repair shop and replace it.
Release the tensioner in the centre of the belt, and see what happens!
When it becomes loose, when it shows signs of fraying or other damage, when it breaks (but preferably before it breaks).
No unless the belt driving the alternator and cooling fan breaks
If the whine happens when starting to move forwards, and then stops once the vehicle is moving, it could be caused by a loose fan belt. If so, tighten the fan belt, or replace the worn belt.
A damaged radiator fan belt, or serpentine belt, shows signs of fraying, cracking, ribbing, and cording. Screeching or squealing sounds may also emit from the engine area, which indicates a need of immediate replacement or the belt may snap.
Signs that the fan belt on your expedition may be failing include squeaking or squealing noises when the engine is running, visible cracks or fraying on the belt, and overheating of the engine. You might also notice poor air conditioning performance, as the fan belt powers the cooling system. If the belt becomes too worn or breaks, it can lead to engine damage, so it's important to address these issues promptly.
it will temporarily make it not squeek but can make it slip
There is no fan belt it is an electric fan. Are you referring to the serpentine belt?
One thing that happens is the fan blades on the transmission get bent up into the drive belt and the fan blades throws the belt. The right way to fix is is to replace the fan, but you can bend the fan blades down by hand without removing anything and it seems to work just as well.