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2002 chevy trailblazer_lt
12 Posts
Discussion Starter #1
Vehicle 2002 trailblazer LT, ~150k miles.

The weather finally cooled off here so I drove home from work today with the ac off and windows down. I was about 5 minutes from home when I noticed that when I came to a stop light (or any complete stop), I started hearing an intermittent (every 10 to 20 seconds) knocking noise. The noise would last for maybe 2 to 4 seconds or so. When I accelerated and drove, it was not making the noise. So when I go home I looked under the hood and could not “see” anything but the intermittent noise continued. I looked at the belt and it’s probably time to replace it, since it was showing a few cracks but I didn’t think the belt would cause the type of noise I was hearing. So I turned the ac back on and the noise/knocking stopped. Then I turned the ac off and the noise came back, again, intermittently and not constant.

So does this sound like the compressor pulley is bad or something else. I would have thought if it was bad it would make the noise when the ac was running, not when it was off. Or does it have something to do with the belt?

Any help or advice would be greatly appreciated. Thanks.
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