2012 Nissan Altima Rattling When Cold: Likely Causes and Checks
2012 nissan altima rattling when cold
A 2012 Nissan Altima rattling when cold often comes from a loose exhaust heat shield or a problem with the serpentine belt system. A loose heat shield can rattle during a cold start after repeated heating and cooling. A slipping belt, worn tensioner, or worn idler pulley can also make a squeaking or rattling sound that is louder when the engine is cold.
Check the heat shield under the car first if the noise sounds like a metal rattle. Heat shields can loosen over time, and the noise may be strongest during startup. Checking the serpentine belt, tensioner, and idler pulley can also help narrow down the source.
The alternator may add to the noise in rare cases. After startup, the battery voltage is at its lowest, so the alternator works hard for the first few moments to restore voltage and current. That extra load can make a belt or pulley problem more noticeable.
If the noise starts when the AC runs, the AC compressor may be failing. The sound can also point to a CVT problem when it comes with strong vibration and knocking while the car idles in drive, with the noise becoming less severe in neutral.
Investigating the heat shields and serpentine belt system can help diagnose a cold-start rattle. The sound's link to the AC, the presence of vibration, and the difference between drive and neutral can help separate an AC compressor or CVT concern from a heat shield or belt problem.
Likely sources
- Loose heat shield Check under the car for a loose exhaust heat shield that rattles during cold starts.
- Serpentine belt system Inspect the belt, tensioner, and idler pulley for a cold-start squeak or rattle.
- AC compressor Consider the compressor if the rattle is tied to the AC.
- CVT transmission A severe vibration and knocking sound that lessens in neutral may point to the CVT.
Common Sources of Rattling
Other Potential Causes
Could investigating the heat shields or the serpentine belt system help diagnose the issue?
Bottom line
A rattling noise in a 2012 Nissan Altima when cold often indicates a loose heat shield or an issue with the serpentine belt system.
Community answers 20
What others in the community said:
If it sounds like a rattle. Check the heat shield under the car. They tend to get loose. I removed mine.
hello i know absolutely nothing about cars, just wondering if anyone could give me any info on what this sound might be coming from before i take it to a shop
Hey guys. Got this car back in December 2018. It snowed a couple days ago and ever since then, my front right area has been making spontaneous "rattle" noise. Kind of like using a wooden spoon and hitting the inside of a tin can.. Also, it seems to only have happened for a few seconds when accelerating a little quickly up a hill.
Do you guys have any ideas?
Is it something major?
So basically I’m trying to figure out what’s wrong with my car. When I drive it or especially when I accelerate I hear this loud high pitch buzzing noise (I’ve seen videos on cars making a humming noise but mine sounds different) kinda of like the noise from flying a remote control helicopter. Also it seems to be kinda shaking like there’s something wrong with the gears if anyone might know what’s wrong id appreciate if u could help me out thanks
Like the title says, it’s a 2008 with about 124000 miles. the sound occurs upon a cold start and then dies down after driving. the sound is more of a rattle. I had to get the AC replaced 2 years ago and the sound seems louder when the AC is on.
My 2013 altima when cold start everyday it makes huge squeaking sound but after that the sound goes away and comes back the another day cold ignition.The sound lasts for like 20 seconds. The belt also makes small squeaking sound consistently but not loud
I’m posting on behalf of my sister, who’s been having an issue with her 2012 Nissan Altima S Coupe. There’s a rattling noise coming from the engine area that sounds like something could be loose or broken. The noise starts when she’s driving or idling, but it stops when she switches to neutral or after the car has been running for a while.
We’re not sure if it’s an exhaust issue, engine mounts, or something else. Any advice or suggestions on what this could be before taking it to a shop?
Hi everyone. I have really been struggling with my 2012 Nissan Altima 2.5S. 90000 miles and has a been a great car up until about a year ago. Power steering fluid leak fixed, oil cooler leak fixed, smaller things like that. I purchased new and have maintained it. I have been working on my cars for ~20 years.
I wanted to be proactive and change spark plugs about a month ago. Went to remove the first plug and there was oil in the well. Decided to stop, dried up oil in well, and got parts to do valve cover.
Changed valve cover/gasket and installed new Bosch plugs and NGK boots.
Car had slightly higher rpms at cold startup but didn’t think anything was wrong. After a few days engine started to misfire. I did some research and it sounded like I should use OEM plugs. I purchased Nissan plugs from the dealer and replaced the Bosch plugs. Misfire went away, but higher rpms at cold start persisted.
After a few days of regular driving, on one journey around town, the car stalled 3 times. All three times when slowing/coasting to make a turn. After the one particular journey, the car hadn’t stalled. However, cold start rpms were even higher at startup, ~2000 rpms. After a few days of driving, I was able to get a code to come up. P050B Cold Start Ignition Timing Performance.
I did some more research and decided to replace the camshaft and crankshaft sensors. Purchased OEM Denso sensors. Replaced the camshaft sensor and went for a test drive. Car seemed a bit smoother, but still high rpm at cold start.
I replaced the crankshaft sensor and this is where things took an unexpected turn. Car started up fairly well, however, after about 1 minute into the road test, the car stalled and now acts like it does in the video.
I tried the old camshaft and crankshaft sensors, combination of new and old, and they didn’t seem to make a difference.
I tried removing the battery terminals to reset the computer, but that didn’t work. I went back the next day and reinstalled the new camshaft and crankshaft sensor and the car started up and was running smooth. No high rpms at startup either.
I let the car run in idle for 20 minutes and as soon as I started driving it stalled. Now the car is back to the same state as the video. The multiple misfire code P0300 is also coming on as well. I again tried to installed combination of the old/new sensors. Nothing is working.
I am beyond frustrated at this point. Car had high rpms at startup, but was mostly driveable before changing the camshaft and crankshaft sensors.
Anyone have any ideas what I should do to troubleshoot a fix? I appreciate any help!
Def sounds like heat shield
So I bought this car a little over two months ago and about a month in it the AC stopped blowing cold.
Originally it took a while to cool off, then it would blow cold and kind of freeze ? Where it was still blowing cold but not hard. So I’d have to turn the AC off, allow it to unfreeze, then turn it back on and it would blow fine again.
After a few weeks of that it stopped altogether. We found out the compressor wasn’t turning on and had a mechanic friend replace the compressor along with a few other things. He didn’t have the tools to do a recharge so we took it after to a shop for the recharge.
Picked it up an hour ago and it blew cold for maybe two minutes. Then stopped. Now it’s making this noise when we flip the AC on. (Video attached via link)
Could be a baffle inside muffler, had that happen once.
belt is slipping. most times on the servo pump. replace belt and tensioner.
Most likely belt and tensioner, in rare occasions it could be alternator as your battery voltage is lowest after startup and the alternator field coil will be at 100% for the first few moments after startup to make as much voltage/amps as it can to replenish
The engine sounds normal. I would check around and see what’s rattling. If you have to, take a long screw driver to the part you suspect is shaking and put your ear to the end of it. It acts sort of like a stethoscope to pinpoint the sound.
Sounds like something came loose. But nothing too serious.
That sounds like a helicopter.
"Get to the Chopa!"
Does the car drive smoothly or does it lurch and grind as you change gears
- AC Compressor: If the rattling is specifically tied to the AC, the compressor might be failing.
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