popping noise on the 2.5s AC?

[fadij]

so i took my car to the dealership several times complaining of a popping noise from under my vehicle while in idle and in park after been warmed up. they checked it out and they said that the noise was coming from the "pre-exhaust" and they replaced the "pre-exhaust" but the noise still was happening and they are clueless to why its doing that...i honestly don't think that's where the noise is coming from but they refuse to check it out anymore so they said they will research it and give me a call...that was 6 months ago...anyone else had this problem and actually got it fixed? its freaking embarrassing.

[rennisouth]

I have the same exact problem and it is freaking annoying as hell. I have no idea what it might be but yes it is embarrassing.

[boystar22]

Same noise here, it drives me crazy too. =(

[ESP]

Huh...I just started hearing it a couple of weeks ago. Freaked the crap outta me at first.

[2008AltiCoupeDan]

nothin here- an now since seein this- i'm listening for it lol

still nothin tho

[bravey_z12]

wht kinda noise u guys talking about i havent got that prob,lucky so far

[boystar22]

It sounds like "thunk" and it happens randomly both when idling in gear and in park, both when the car is warm and after its been shut-off. I can feel the thud of whatever it is on the floor of the car, but it doesn't do it in any set interval so I can't ever record it, or find it. I notice it mostly in drive-thrus or sitting in traffic at red-lights, but it also does it 3 or 4 times once its in the garage cooling off.

It isn't normal exhaust expansion and contraction, I can hear that too. This sounds like a much more severe version of that.

[fadij]

It sounds like "thunk" and it happens randomly both when idling in gear and in park, both when the car is warm and after its been shut-off. I can feel the thud of whatever it is on the floor of the car, but it doesn't do it in any set interval so I can't ever record it, or find it. I notice it mostly in drive-thrus or sitting in traffic at red-lights, but it also does it 3 or 4 times once its in the garage cooling off.

It isn't normal exhaust expansion and contraction, I can hear that too. This sounds like a much more severe version of that.

what did the dealer tell you?

[boystar22]

I haven't bothered to take it in yet. My dealer hasn't been the most caring in any of my issues. The service manager didn't feel the rust on my week old car was a warrantied item. I'm hoping someone else finds the problem and the fix first.

[ESP]

It sounds like "thunk" and it happens randomly both when idling in gear and in park, both when the car is warm and after its been shut-off. I can feel the thud of whatever it is on the floor of the car, but it doesn't do it in any set interval so I can't ever record it, or find it. I notice it mostly in drive-thrus or sitting in traffic at red-lights, but it also does it 3 or 4 times once its in the garage cooling off.

It isn't normal exhaust expansion and contraction, I can hear that too. This sounds like a much more severe version of that.

That's exactly what it's like (only it happens just once for me, not 3 or 4 times in a row). Most often it's when I'm parked (when it happens in the garage when I've turned the engine off it's pretty loud), but occasionally it does it when I'm idling at a drive through/red light.

@ Boystar: What kind of exhaust system do you have?

[boystar22]

My exhaust is stock, I haven't changed anything there. Mine doesn't do it three or four times in a row either, it's completely random, but it will usually do it three or four times randomly after it's been shut off and it's cooling down. I walked by it the other day after it had been sitting for over an hour and it popped. It sounds like a heatshield under the center of the car that has a loose weld that's letting it expand and contract too much and it knocking on the floor pan, but I've crawled under it and haven't been able to find anything.

[papachristosj]

I was just at the dealer for this dumb problem. They thought my pre-pipe had a leak so they replaced it. To no surprise it's still making that noise, my friend who's a respectable mechanic said it's just a simple cooling feature that only certain exhausts make, such as our coupes.

If we were to replace our stock exhaust system there would be no more pinging.

[boystar22]

If it were a "feature" wouldn't everybody's do it though? Since its only showing up on certain 2.5's I'm led to believe it was a problem on the assembly line. Maybe its only happening to 2.5s built in Tennessee (like mine), and not the ones built in Mississippi. *shrug* Its way to embarrassing of a sound for it to be considered "normal" by any means.

[ESP]

I was just at the dealer for this dumb problem. They thought my pre-pipe had a leak so they replaced it. To no surprise it's still making that noise, my friend who's a respectable mechanic said it's just a simple cooling feature that only certain exhausts make, such as our coupes.

If we were to replace our stock exhaust system there would be no more pinging.

LIES LIES LIES!!!

If it was a "simple cooling feature", why would my car start doing it only two or three weeks ago when I've had it for over a year. Also, I did replace the stock exhaust system...the popping began after I replaced it...

...still a mystery.

[2008AltiCoupeDan]

ok- so the only thing i've heard the past dayish or so- is if i drive 'normally' i got no sound.

if i gun it in first and do a semi hard shift into second at like 4-5k rpms theres a 'click' after i slam the clutch lol

otherwise nothin.

are all u guys hearin this w/ cvt...?^^NOT trying to start a war^^ just curious. esp since me an bravey w/ our 6spds havnt had this sound.

[boystar22]

Mine is a CVT, but since it does it in drive and park when everything is disengaged and when the car is completely off I'm not so sure it's really transmission related. I suppose it could be getting hot and making the heatshields around the exhaust expand toward the exhaust rather than away making it pop back and forth. I still think that's stretching it though.

[QR25DE]

Mine is a CVT, but since it does it in drive and park when everything is disengaged and when the car is completely off I'm not so sure it's really transmission related. I suppose it could be getting hot and making the heatshields around the exhaust expand toward the exhaust rather than away making it pop back and forth. I still think that's stretching it though.

Most cars do this when the heat shield is hot and it's cooler outside. I get the same thing too on my 2.5... every other car i have has done it too... neons, corollas, stanzas... same s***, different car. Unless we're hearing different noises.

[boystar22]

This isn't the normal ticking and clicking that an exhaust makes when it's heating up and cooling down. This sounds like someone is throwing a tennis ball at the hood (only it feels and sounds like it's under the floor). I don't know how well I can describe this, but if you've ever had a hood or door or something sheet metal with a dent in it that you can "pop" out, only to have it dent back in when the temperature changes, it's that sound exactly. It sounds like a heatshield has a dent in it and when it gets hot and expands it pops out, but when it cools off it dents back. That's the best description of the sound, however since it continues to do it rather than just once when warming up and once when cooling down it couldn't just be a dent in the muffler or heat shield.

I feel like I just wrote a book that no one but me will understand...

[fadij]

This isn't the normal ticking and clicking that an exhaust makes when it's heating up and cooling down. This sounds like someone is throwing a tennis ball at the hood (only it feels and sounds like it's under the floor). I don't know how well I can describe this, but if you've ever had a hood or door or something sheet metal with a dent in it that you can "pop" out, only to have it dent back in when the temperature changes, it's that sound exactly. It sounds like a heatshield has a dent in it and when it gets hot and expands it pops out, but when it cools off it dents back. That's the best description of the sound, however since it continues to do it rather than just once when warming up and once when cooling down it couldn't just be a dent in the muffler or heat shield.

I feel like I just wrote a book that no one but me will understand...

you wrote all of that explaining what it is and by the end of the last sentence you said it count be what you f***ing wrote!

[boystar22]

I was describing the actual sound, so everyone would understand it isn't normal exhausting expansion sounds. I still have no idea what is causing it or where its coming from i just want everyone to know it sounds nothing like normal ticking and clicking.

[fadij]

they need to do something about this ASAP

[Chiefster]

I posted this issue like 2 weeks ago on a different thread........its souunds like a clunk sound and it feels like its coming from the bottom of the car....i think if alot of cars are doing it,then it is normal,but still scares me and is embarassing if people are inside my car.

[DiamondWVU]

i have it too. but it was only in the winter. once it started getting hot out it didnt make it anymore. i guess ill see if it starts back up when it starts to get colder again.

[scannon]

I have the same exact problem. They replaced the intermediate pipe on my exhaust. Said it was a baffle noise or something. Guess what? The car is still making the noise. They tried to tell me its normal expansion noise. Anyone who has this problem knows its not normal. Very aggravating. They keep telling me to come with them for a test drive. I told them you can't hear it while you're driving - only idling. Anyone have any idea what it is?

[2008AltiCoupeDan]

ok- i got it- lol .... ive been listening for it day in and day out and now the other week i heard it. i was dropping off my gf after a night on the town and i go to open her door and as i open it i heard what sounded like a marble hitting a metal thing. but it doesnt bounce - it just hits and is done lol and now whenever i drive, i hear it when i stop and am about to turn the car off. its sorta annoying but im with u all now lol- just took me a lil to notice

[boystar22]

Yea, it isn't until you've actually heard the sound that we're all describing that you understand how annoying it is, and how it couldn't possibly be considered "normal".

[heavymetal]

That sounds very annoying. I'm about to buy the 2010 2.5s when it comes out next month.. i'm worried that this is a perpetual issue.

I see on this thread it has affected both 2008 and 2009 models.. does it seem limited to the 2.5? or is it on the 3.5 too? can anyone confirm. That's really s***ty that nissan won't narrow it down.. i'm starting to wonder if this is a car that company i wanna deal with long term.. maybe i should stick to honda.

[heavymetal]

Could it be related to the bose stereo. It was mentioned in this post (see below) in this forum:http://forums.altimas.org/zerothread/278693

But seriously, I've had the exact same problem. The plastic piece surrounding the headunit of the bose system makes noises when the inside of the cabin becomes really hot. But since I got my tint, I haven't had to deal with it again. It was really annoying and pissed me off. But now my driver's chair kinda creaks when I lean back on it.....reallllly annoying....don't how or what they would do to fix THAT....

[mellyrose]

I bought my 2009 2.5SL sedan on July 17 and noticed a popping/knocking sound just a couple weeks later. Like others, I can describe this as sounding like a ball hitting the car, or like a dent popping out, it's LOUD, startling and embarassing...and it only seems to happen after I've been driving for a bit and then I come to a stop or slow in traffic. Once it starts to cool down and after I shut off the engine completely, it continues for at least 15 minutes.

I took it to the dealer twice, both times they returned it with the result "checked out ok," which I knew just meant that they didn't drive it enough or know what to listen for and when. Finally, I started researching on my own and found some information regarding heat shield problems and the sound it makes, which is explained EXACTLY like what I've been hearing. I took it in again today, for a third time, and after the service manager mocked and laughed at me for looking for answers on the internet, I had him ride with me for 20 minutes until the sound started, and once it started, it didn't stop...even after I turned off the engine. He was MUCH more polite to me once he heard it too. He then became baffled and determined to figure it out, though he admittedly had no idea how to figure it out.

He then went and talked to some of his mechanics, and it turns out that the 06-07 Altimas have already had a bulletin put out about the heat shield design and the knocking noise it makes when it heats and expands. The 2009 bulletin hasn't been issued yet, and until it is nothing can be done, because they need to put out a NEW PART to fix the design flaw. I called 1-800-NISSAN-1, per my dealer's suggestion and told them about this. I think EVERYONE should do the same. The more complaints the manufacturer gets, the more likely this will be addressed.

Good luck to everyone. In the meantime, turn your radios UP to try and drown it out!

[heavymetal]

does this problem only exist on the 2.5 or is it on the 3.5 as well? what is the likely-hood they would have fixed this for the new 2010 model.