Popcorn-sounding noise - ideas?

rtbrick · October 3, 2004

Was driving today and noticed a noise that sounded like popcorn popping in the microwave. Maybe a slight metallic sound to it. I though it was coming from the forward portion of the transmission tunnel. Wife thought it was the passenger side rear area of the engine compartment. Didn't really hear it much except at about 45 mph. Third and Drive gears. Could it be a transmission issue? The noise was not constant; rather, it was somewhat irratic and intermitent. I got out twice to look for something loose knocking around in the engine compartment. All opinions welcome!

citydriver · October 3, 2004

Was driving today and noticed a noise that sounded like popcorn popping in the microwave. Maybe a slight metallic sound to it. I though it was coming from the forward portion of the transmission tunnel. Wife thought it was the passenger side rear area of the engine compartment. Didn't really hear it much except at about 45 mph. Third and Drive gears. Could it be a transmission issue? The noise was not constant; rather, it was somewhat irratic and intermitent. I got out twice to look for something loose knocking around in the engine compartment. All opinions welcome!

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Were you accellerating when this happened? pre-ignition "ping" due to bad gas

Could be a u-joint goin bad...just a couple of guess'

JamesF · October 3, 2004

Was driving today and noticed a noise that sounded like popcorn popping in the microwave. Maybe a slight metallic sound to it. I though it was coming from the forward portion of the transmission tunnel. Wife thought it was the passenger side rear area of the engine compartment. Didn't really hear it much except at about 45 mph. Third and Drive gears. Could it be a transmission issue? The noise was not constant; rather, it was somewhat irratic and intermitent. I got out twice to look for something loose knocking around in the engine compartment. All opinions welcome!

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I've got an 04 Z71 Sliverado with 2700 miles on it and I've heard a real similar noise twice since I've had it. Yesterday was the last time. Nothing I've ever heard a vehicle make before. Lot louder than a ping and to me sounded like it was under the truck and to the rear. Unsure left,right or middle. Yesterday I had the driver window down. I hadn't driven 1/4 mile from the house and wasn't doing more than 30 accelerating up a slight hill. Didn't feel like I was losing any power and didn't feel any vibration, just made the weird noises. For a sec I thought it was the reflectors in the road but the noise stopped after 5 seconds and I ran back over the reflectors and nothing.

James

rtbrick · October 3, 2004

My noise is fairly constant. I'm not sure how long it has been going on because it is hard to hear over the radio. I had turned the radio down to talk to the wife and then I heard it. I don't feel any loss of performance, although the transmission shifts a little loose. That's why I thought transmission.

electromag8 · October 3, 2004

My trucks seems to have developed a similar noise. I'm pretty sure that it is an exhaust leak somewhere in the monifold area. I only hear when the truck is under load, (like up hill), you can't hear it if you pop the hood and listen at idle. A friend told me the the exhaust manifold may have a crack, but we will have to remove the heat shield to investigate further.

ktmjim215 · October 3, 2004

I see in your listing that you have a bug deflector. The noise caused by wind deflection on the RT & LT windshield strips has been described as "angry crickets" to "popcorn". The noise comes and goes, depends on the wind. Try slowing down or move in behind a semi to change the airflow when you hear the noise and see if it changes. The location of the noise can be hard to follow at times.

If the noise is constant enough, cover the side moldings where they touch the W/S with masking tape and if that's your noise it will stop. The problem can be fixed with double sided tape behind the moldings. Just a suggestion.

rtbrick · October 3, 2004

I've read about that on the forum, but is that something that would just start up after almost 5 years? I'll try the masking tape test, though. The tracking behind a larger vehicle is a good idea as well, but if it is mechanical in nature I'm a little leery about chasing down semis on the interstate. LOL!

ktmjim215 · October 3, 2004

The noise from the strips can increase as the moldings become more pliable and easier to move. You can stay 8-10 car lengths behind a semi and change the air flow. Ask any motorcycle rider.

rtbrick · October 4, 2004

On the way to work this morning I was able to drive behind a few other vehicles as well as alone. I only heard the sound when driving alone. So I guess my truck has developed the molding sound. I'll have to apply one of the fixes on the forum here. That sure is a nasty sound for it to be the molding. I almost wanted to pull over and have it towed home when I first heard it.