Problems with idler pulley.
Serpentine belt idler pulley noise.
It helps move the other engine accessories too.
If the idler pulley is misaligned then the serpentine belt will make noise.
If the pulley is making noise either it s the result of a bearing failure or the spring is not providing the proper tension.
If your idler pulley is worn and the grooves do not hold the belt firmly you will hear a squeaking noise from the engine.
The pulley itself has an outer ring and an inner bearing.
Aside from the pulley of your drive belt tensioner the idler pulley can cause the serpentine belt to make noises too.
Any problem in the system will create idler pulley noise indicating there is.
In extreme cases the idler pulley will fail completely which means that the vehicle will not move.
The idler pulley is another one of the pulleys which help keep the serpentine belt moving.
The idler pulley ensures the correct tension of the drive belts.
If the noise stops until the water dries up then returns there is either a miss aligned pulley first suspects would be worn idler or tensioner pulley bearings or the belt s and or pulleys ribbed grooved surfaces are worn and need replacement.
An idler pulley or engine pulley steers and tensions the engine drive belt serpentine belt which drives several engine accessories including the power steering pump alternator ac compressor and water pump.