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2010 Toyota Corolla LE Random "Rapid Gunfire" noise

I have had my Corolla LE since October 2011, there has been no maintenance issues whatsoever with it, and it has 65K miles on it. Up until September it was a solid, quiet ride, and with the passing two months, what started to be a quiet vibration, has grown louder and louder. At first I thought it was something inside one of my storage compartments rattling, and then I thought it was the blower, only noticing the sound when I turned on the heat. Now, it makes noise when I accelerate, decelerate, at a complete stop (with the car still on). I read another post about it might be the heat shield, and I was convinced previous to reading that that it was something exhaust-related. But, I’m not sure. This noise has gotten louder, isn’t consistent with any function of the car, it appears to be random, but the noise is still the same, the quick “drr, drr, drr” noise, truly a rapid gunfire sound. Any thoughts? I really don’t want to pay a ton to have someone diagnose it to tell me it is nothing, or I am “making it up.”

Pretty hard to diagnose a noise from 1000 miles away. You’re either gonna have to localize it a little or just have someone take a look. I can’t see being charged to tell you if you have a loose heat shield, axle coming apart, heater motor, or a hundred other things, to give you an estimate on the cost.

Open the hood, put your head under it, have a friend revv the engine a bit, and see if you can tell where it’s coming from. And check your fluids while you’re there. It could be something as simple as the hood supprt rod rattling in its hole, it could be an exhaust leak, or it could be much more serious, like a bearing knock. There’s not enough information here to begin to diagnose the source, but if you’ll post the results of your look-see we might get lucky.

By the way, do you monitor your fluid levels?

As mt bike says, when there’s a small exhaust leak before the cat/muffler, sometimes this occurs at the exhaust manifold or cylinder head too, it can sound very similar to gunfire. Pop, pop, pop kind of sound. But I wouldn’t call it “rapid” like a machine gun, so I’m expecting your noise isn’t this. If it is an exhaust leak, the individual pops are easy to hear at idle. One way to tell if this is the problem is that the rate of the pop’s would be low at idle and increase with rpm.

There is a recall out for water pumps of this year. Thats what was causing mine to make that noise.

I would check the cooling fans. It sounds like something has come loose and when the fans come on, the blades of one of them is hitting something.