For several months, my 2004 VW Passat (1.8L Turbo FWD) has been making an intermittent squeal while driving. The noise is brief (lasting usually a fraction of a second), is loud, screechy and high-pitched (like a belt slipping), sounds as if it’s originating from the rear passenger’s-side area, and always occurs just after I begin to drive after being stopped at a light or stop sign. It occurs most frequently when I make a left turn (never a right turn) and sometimes when proceeding without a turn. When it’s heard while driving straight, it’s accompanied by a momentary hesitation in speed, but whether this is just engine hesitation or active deceleration I cannot tell. The problem began in the fall of 2011, stopped during the cooler months (I live in southwest Florida), and began again once ambient temperatures climbed again into the 80’s. It usually occurs once or twice per day (but some days not at all) and typically in the afternoons when the air temperatures are warmer. I never hear it when the brakes are applied, and the brakes do not squeal. The noise is not accompanied by any dashboard warning lights.
My local VW dealership claimed that the cause was rusty rotors (as I had recently moved to FL from New England), and I spent several hundred dollars having the rotors replaced, only to have the problem reoccur as I was leaving the dealership’s parking lot. I now have an independent mechanic who has been road-testing the car for several days and has heard the squeal once but is puzzled as to its cause. There is no uneven brake wear to suggest that the calipers are being applied unevenly. About 2 months ago, when the squealing noise was absent in the winter months, my mechanic removed a 6mm piece of aggregate which had become lodged beneath the vacuum plate of the rear driver’s-side brake assembly. However, a month later, the squeal returned as before.
My mechanic is truly puzzled and at this time can only suggest having the rear brakes and calipers replaced. Anyone out there have a similar experience or suggestions?