Anytime my fan is turned on, it "squeaks" or "squeels" at a variety of volume levels, depending on the day. I went through a period of about a month in the winter where the fan did not work at all, but when I threatened to take it to the shop, of course, it begins to work again. It will sometimes cease to work while I am driving after no certain amount of time running (pretty random). Will it need to be replaced or does something need to be tightened?--the dealer says replaced ($500). Had same trouble with '86 740.