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What in the heck kind of noise was this? loud moan after starting car.

19K views 21 replies 13 participants last post by  tkc330cic 
#1 ·
I did a search and didnt find anything exactly like I was describing. I drove my 2012 Overland V6 4x4 to grab some food this evening. Outside temp was very hot upper 90's. Went inside and came back out 5 minutes later. I started the Jeep and a loud moan humm kind of sound occurred right after starting. It only lasted about 2 seconds, but it was loud enough to almost startle me. If I had to guess it sounded like it came from directly under the center of the vehicle, but this is just a guess. It only has 4400 miles with no known issues. I think I remember this noise happening once before (although not as loud) and I didnt think much of it.
If it makes a difference I drove to get food in sport mode and parked it in park mode. Went in for 5 minutes and came out and started it. After the noise everything was perfect as usual.
Any ideas what the heck this was? Please dont say its normal operation because no one should EVER actually get startled from a loud noise after starting their new 40,000+ thousand dollar Jeep lol.

Im all ears :)
 
#3 ·
No it definately was not any sort of fan. The cooling fan is at the front of the vehicle and this sound came from what seemed like under the car, and it was a loud moan sound that can't picture any fan making, more like something mechanical I guess.
 
#7 · (Edited)
Hi There,
I managed a recording of mine a couple of weeks ago. Still does it, today was the loadest and is becoming a joke, now lasting a good two or three seconds. (The zip file is safe. Contains two recordings). My fellow Aussies reckon it could be the aircon pipe hard up against the firewall. The noise is VERY loud and vibrates through the cabin, and steering wheel.

See post 12 on this link and ignore the witty Australian commentaries!!:lol:http://jeepgarage.org/showthread.php?t=43990http://
 
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#9 · (Edited)

Hi There,
I managed a recording of mine a couple of weeks ago. Still does it, today was the loadest and is becoming a joke, now lasting a good two or three seconds. (The zip file is safe. Contains two recordings). My fellow Aussies reckon it could be the aircon pipe hard up against the firewall. The noise is VERY loud and vibrates through the cabin, and steering wheel.

See post 12 on this link and ignore the witty Australian commentaries!!:lol:http://jeepgarage.org/showthread.php?t=43990http://

WE GOT A WINNER!!!!

That was EXACTLY the noise that my Jeep made. I didnt necessarily get the vibrations you spoke of, but without a doubt got all the noise and it was loud.

Ok so whats my next step to fixing this? Also, I read through some of your posts and noticed yours actually does it while you drive? Mine did it just after starting my Jeep. Have not heard any noises yet while actually driving.


Thanks so much for the help. LOVE this forum :)
 
#12 ·
Feel free to thank me and/or add a one of those nice looking emerald spots:thumbsup: Only kidding. Glad to help. It was driving me crazy. Usual case, I could not replicate the noise when I took the car into Service...the manager thought I was an idiot making grunting noises in his office an attempt to replicate the noise! I self diagnosed the root cause of the noise myself one evening, then caught the recording on my iphone. The service centre have asked to leave the car with them whilst they tear apart. (They admit they do know what they are looking for but ackowledge the noise is AC related) I'd be over the moon if you guys get a more positive outcome that I can take to the Service Dept with a specific fix.

PS Build date 17th March 2012.
 
#14 ·
Hey, Thanks Angler. I'll keep you updated on the fix. heres hoping its something simple and not the compressor clutch.
 
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#15 ·
Guys, heres a thread DownUnder that details events so far. Waiting for a TXV and evaporator to come from the US, but really reluctant to have my dash ripped out. Told it's a total strip back to the firewall by Jeep Service!!

http://jeepgarage.org/showthread.php?t=45378
 
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#18 ·
ROFL ! I just heard the noise on the ZIP file. I thought you might have been calling Sheep or sumfin! :lol:

But in all seriousness I had this issue this weekend one time as well. I thought it was my Wheel as it started right after a started to pull away.

Was hot and humid too.
 
#19 ·
It's an anomaly with the AC system that I've experienced a few times on vehicles over the years and yes I did have it happen (twice) on my WK2 the past two years. An HVAC engineer explained it to me many years ago but I can only recall this: it is the system equalizing a large pressure change.

Think of it like letting air out of a balloon connected to a larger volume container: if you let air out carefully you get no noise but the whoosh of airflow; if you try forcing air out too fast you get the funny "plgghhhhh" fart noise or in the case of a vehicle AC system, a momentary groan. The AC system making that groan is doing that with the same effect as the balloon example when you have the system working hard, shut it off, then turn on again later.

It should be a very rare occurrence and if not, could mean a problem with the compressor/lines/valves. I would recommend the dealer checking your refrigerant but leaving it alone if the noise only occurs infrequently. You open a bucket of worms tearing apart the HVAC system chasing what could just be an occasional annoyance with no guarantee or curing it.
 
#21 · (Edited)
Here is the sound in all its glory I posted to YouTube!! Still as bad as ever now Springs arrived and the temps are averaging mid 20's C (high 70'sF). Hopefully get a fix before Summer!

http://www.youtube.com/watch?v=uC-Kxe3jDXA
 
#22 · (Edited)
My 2005 JGC 5.7L was also doing this. I bought her only about 3 months ago, so I'm still finding the little things here and there that need fixing.

It's been really hot here in Texas and I've been running the AC full blast all the time. About 2 weeks ago, I noticed that when I came to a stop light or was just slowly driving through parking lots, the loud moaning would come from the front. At first I thought I was low on power steering fluid. I checked and the fluid was at the "minimum" line, so I thought I'd top her off and hope that solved the problem. I bought the OEM Mopar stuff, topped her off, but then later that day, the moaning was back. I stopped the jeep, put her in park, tried to center the steering wheel, but the moaning kept going loudly. Then I decided to shut off the AC so I could hear it better. A few seconds later after shutting down the AC, the moaning stopped!

This issue continued for the next couple weeks. During cold start, there didn't seem to be an issue. It only would happen after the jeep was hot and I had been driving a while with the AC blasting.

Then I seemed to notice the AC wasn't very cold, especially on blistering hot afternoons. I got one of the cheap AutoZone refill kits and put the pressure gauge on first to see if it was full. It said it was, but I know these cheap systems have crappy gauges, so I didn't really trust it.

I took it in to a shop on Monday and they said there was a slight leak at a connection near the high valve, so they said they fixed the connection and drained and re-filled the AC system. Now I have cool AC again and the moaning hasn't come back. It's been 4 days now so hopefully this solved it!

Good luck to everyone with the issue! I hope you get it figured out.
 
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