Automotive question: what the HELL was that noise?

Factual Questions
1

My 2000 Saturn Wagon is one payment away from being really and truly mine. Which means, naturally, that I expect all hell to break loose, automotively speaking, about this time next month. For the most part, however, it seems to operate pretty well. Last evening, however, it scared three years off of my lifespan.

I was driving on the freeway, averaging about 60, and I noticed a sound that might best be described as a lot of sand and a few small pebbles churning about in a dishwasher. I took a moment to check the cars around me and make sure that it was, in fact, my car making the noise. Once this was confirmed, I hit my right blinker and started to slide over towards the upcoming off-ramp. As I tapped my brake to slow down, I heard a shrill shrieking noise like a clarinet on the first day of band practice. Each time I pressed down on the brake, the noise repeated. Once off the freeway, I continued slowing down – other than the noise, the brakes appeared to be working properly. All at once both sounds – the dishwasher and the clarinet – stopped completely. The whole incident lasted about, I’d guess, 45 seconds to a minute.

I drove the rest of my way to rehearsal (about 5 more miles) via an off-freeway route, listening frantically. Neither noise came back, and I noticed nothing different in the performance of the car. When rehearsal ended, I drove home via my normal route and again noticed nothing unusual.

So what on earth could this have been, and how worried should I be?

2

You probably picked up some fine grit or a small pebble in your brakes. When you apply the brakes, you’re grinding the grit into dust, which then goes away. If you haven’t had the brakes checked since you bought it, you might think about doing that.

3

Seconded. My wife got a small pebble lodged in her brakes, and it would make that shrill clarinet sound when she drove forward, and a rattling sound as she backed up. I had to pick it out with a mechanic’s retriever.

4

Yep, I go offroading in my Jeep and that happens a lot. It’s possible that it cut a groove into your rotor, which will wear out your brake pads faster. Get it checked.

5

Thanks very much for the replies. I will get the brakes checked out.

6

This usually happens due to mud. The mud has grit and gravel in it. When it dries, it falls loose and ends up where ever.