Strange noise leads to a rattle?!

[ck1995]

I have had a strange noise that comes and goes. It is hard to describe and other than it only lasts for a second and it comes from under hood not sure what to say about it. I get noise while at idle, accelerating, braking, turning, straight, etc. Can't make it repeat, it just happens, it is kind of like a whine mixed with a squeak. Anyway, today it progressed to a constant rattle that sounds like it is coming from the fan area. The belts all look fine and fan appears to operate O.K.

Maybe it is a pulley or one of the accesories or fan or fan clutch??? Without just replacing everything I am unsure.

BTW it is my E34 w/ approx 150 on the clock........

Any ideas appreciated,

[whiskychaser]

Water pump bearing?

[Ross]

Water pump bearing about to explode is my guess. Loosen the belt and see if it's wobbly. Also check the fan clutch.

[Bin_jammin]

Actually, from what he's describing, it sounds to my ear (eye?) like a belt tensioner. What type of belt tensioner does your engine use? It is a serpentine belt isn't it? Take the tension off the belt and wiggle/wobble each pulley to see how much play it has.