2012 Chevy Impala has a rattling noise

This would depend on if it is coming from engine or not,if it is from engine,it may be bad lifter or valve rattle.

Well when I bought the car from the dealer he said it had something loose by the exhaust, but u know how car salesmen are, they tell u anything to get your money. But it sounds like to me the noise is coming from underneath the car.

TST is right on, just let it cool down a while before you start wiggling things under the car. Cats get hot REAL hot

Good evening FN,

Yea that's what my uncle said who runs a mechanic shop. He said that if it's not losing power it's not the catalytic converter, it's probably the heat shield that goes around the converter. So, Monday I'm gonna go to his shop hook it up to diagnostic machine and then hopefully just lift it up and tighten the bolts that go on the converter cover. I'll repost and keep everyone updated. I love this forum, I'm sooo happy to have u guys in my life :)

So are u saying that the noise isn't coming from there? Or are u saying it is, but the fix won't be as easy as I thought?

We are having the same problem with our 2012 Impala. The dealer said it was just a cold start problem and there was a bulletin out. Our is noisy when accelerating up a hill. Sounds like a race car. Very disappointed in this car. They said they put a whole new exhaust system on but still making the same noise. Do not know where to turn anymore. We are heading back to the dealer again this week to see if they have any ideas.

#PI1138: Rattle/Noise from Front or Rear of Vehicle on Cold Start Up - (Dec 20, 2013) Subject: Rattle/Noise from Front or Rear of Vehicle on Cold Start Up Models: 2012-2013 Chevrolet Impala 2014 Chevrolet Impala Limited Condition/Concern Some customers may comment on a brief rattle or noise heard from the front or the rear of the vehicle on a cold start up. This may be caused by the “Y” pipe inner and outer components expanding at different rates resulting in the rattle/noise. Recommendation/Instructions This is a normal characteristic of the vehicle’s exhaust system and no repair(s) should be attempted for this concern. Customer Information Please communicate to the customer this condition is a normal operating characteristic of their vehicle. It will not impact the designed performance or reliability of the vehicle. Please share this information with the customer, including a copy of this message. For further information, please contact GM Technical Assistance Center (TAC) for assistance.

Did you ever find out what was rattling? Thanks

Its the same sound as i listed with that tsb. Its annoying but goes away and dealers will not fix it. Not sure if spending $1000 on a new exhaust will fix it or the problem will come back.

I have a 2013 Impala that had the loud exhaust noise on start up. I asked at a GM dealership and got the pat answer that it is normal. A year later, after the warranty was out, the thing started to get worse. It makes a buzzing when under mild load and running betw 2k & 2.5k rpms. Get worse with time. GM said it was the Y pipe causing the noise. Fix price $900. Seems it is the flex couplings. Take it to a muffler shop. I'm not convinced that a flex coupling can make that much & kind of noise.

I have a 2014 Impala with rattling noise that comes and gose. We found it to be the backing plate for front rottors. Dealer wont even look at it unless we pay. I guess we'll try to fix ourselves. I hope this is helpful to you. It took us a lot of looking to find the problem.

Ima check this my impala has a small rattle in the front right . You said backing plate?

All this rattling is from the back end

try adjusting hood stops = may be too low. one on each side of hood frame rubber bushing

Guys, that sound is made by the flexible part of exhaust pipe. It's located right behind the rear part of the engine sub frame. The rattle is inside the pipe. Somebody mentioned here that the sound was still there even after whole exhaust was replaced. In your case, it looks like the engine mount may shift the engine position. The flexible part is designed to be stretched, but if something causes the flexible part to not be straight, it will rattle.

I have two 2012's, both have the same rattle at initial start up and upon acceleration when traveling up an incline. One has 43,000 miles the other has 200,000 miles. Doesn't effect the performance but it sure is annoying. Haven't discovered a solution yet. Looking for some solid feedback.

I have replaced everything but the bellows type piece of flex pipe right before the last catalytic converter, there are 2 right after the 2 small cats, those are rubber with metal mesh wrap, those are not the culprit, if you apply pressure on one of the exhaust tips on the rear upon starting cold it will not make the rattle sound, so if you replace the bellows style flex with another mesh reinforced rubber flex tube your rattle will be over, good luck!

There is a service bulletin Bulletin No.: 13-06-01-002 for the need to replace the lifters in the 3.9 engine for free, this will also cause an engine rattle..

2012-2013 impala and 2014-2016 impala limited have a flex pipe that rattles at low rpms. It has to do with the air being pushed through it . the only way to get rid of the sound is with an aftermarket hi flow exhaust kit. These cars r more intended for an enthusiast that wants to turn it into a sports. Lol sorry guys, I don't care what gm dealers tell u. That is the truth. The 3.6l high feature engine was produced by an Australian company called Holden.

It is indeed the bellows of the crossover pipe making this noise, and it is a bitch to remove, but can be done if you have a jack and some jack stands. You have to unbolt front top motor mount, loosen 4 bolts on front cat convertor, remove front wheels, drop the rear of the front subframe a couple inchs, remove pinch bolt on steering rack coupler, lower front subframe a few more inches, remove sway bar, disconnect two fluid lines from steering rack and remove rack, and finally remove crossover pipe. Thank you Chevy engineers. I'm cutting the bellows out of my crossover and replacing with straight pipe. I'd rather deal with a little extra exhaust vibration than that annoying rattle. Complete exhaust is hung in rubber mounts so it has room to expand and contract and vibrate anyway. Also going to remove the resonator while I'm at it and cut the screen out of the small cat in front of the resonator, as it was probably 30% plugged. The crossover pipe has a design flaw so I don't want to waste time and money on replacing it with a new unit. So there you go. Now at least you have an idea how to remove the crossover pipe and get rid of that annoying exhaust rattle. I googled removal of crossover pipe on Chevy Impala and found absolutely nothing on it. Took me about 5 hours to remove it. Now I could probably do it in 3.

wow Gary, you just made me sad lol. I thought all I had to do would be is unbolt it and it would come out as I pulled it forward and it would follow the curve. Guess I will live with the rattle then, if I have to go through all that to remove it.

You might want to check your top engine mount. Mine was actually worse off than I first thought. Both ends of it were sloppy. It only takes about a 1/4" of misalignment for that bellows to rattle. Anyway I took my crossover pipe to the muffler shop and had a piece of flex welded in its place, and replaced the top motor mount, ($38 on Amazon), smoothed out the ride and purrs like a kitten now. It only took 1-1/2 hours to reassemble the front end, so it sounds like a lot, but everything is pretty straight forward, and the flex pipe is smaller in diameter than the bellows, so it might even snake out of there without removing everything else if something should happen to it again. 160,000 miles on this car. Nice ride and everything is holding up nice, and it was only $150 for the repair, so I'm not complaining. Another thing that fails on these cars is the actuators for the A/C controls, makes a loud knocking noice inside the cabin. Both easy and cheap to replace.