I've got a 94 940 wagon non-turbo. lately it's been wet and rainy out here, and whenever it is moist out the car makes a rhythmic squeak from under the hood. It sounds like it might be one of the two belts (I disconnected the AC belt as I don't use it and it doesn't work). One of them I replaced a little while back but the other seemed ok on my visual inspection. I vaguely remember the mechanic at some point brushing a little bit of some grease or other similar substance onto the belt to deal with a squeak--is that something I should try before replacing or is there another technique?