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3.6 Idle Vibration/Smokey Exhaust on Start-Up

1173 Views 3 Replies 4 Participants Last post by  Cadillac Customer Service
I was wondering if anyone could offer some insight into an issue I am having with my 2014 ATS-4 3.6 Premium. Thank you in advance!

I have been having issues with a rough idle, which seems to be prevalent with the 2.0T. The first time I brought it in for service, an update was applied which temporarily corrected the situation. The rough idle came back after about a week or so, and I discussed this with the dealership at the second service.

The second time I brought it in, another update was applied. Upon starting the vehicle, the rough idle was worse than ever. I immediately called the service advisor over, and he said that it was normal for the V6...and there was nothing they could do.

The next day, I also began noticing a large puff of smelly dark grey smoke coming out of the exhaust pipes upon start-up. It was noticeable enough that co-workers commented on the smoke coming from my exhaust. I immediately scheduled another appointment for this issue and for the sunroof recall.

The third time bringing the vehicle in, the dealership kept it for 3 days to delve deeper into the issue. They replaced the engine mounts with the upgraded ones they receive from GM (I was told that they discussed my vehicle with GM engineers in Detroit and these will be shortly be addressed in a service bulletin). The new engine mounts helped a little...there is still a rough idle, comparable to how the vehicle originally was when I first brought it in....annoying and noticeable, but not as extreme as after the second update. They said the exhaust smoke was "normal"...though this never happened before the second computer update.

However, later in the day after picking it up...after the car sat for a while...I went out to run errands and there was a huge puff of exhaust smoke upon start-up.

I'm a bit concerned. I plan on taking a video of the exhaust during start-up over the next few days, making an appointment, and showing my service advisor the video. This smoke is certainly not normal.

Does anyone have any idea as to what may be occurring with my ATS?

Thank you for taking the time to read this tread.
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The smoke upon startup is one of the indications of valve guide seals requiring replacement. Hopefully the stealership looked into that for you. Also, take a look at this thread: Consistent problem with the 3.6 DI engine.
I have a 2014 ATS-4 3.6 with the same idle issue. I have learned to live with it but i'm contemplating the engine mount potential resolution but I am also concerned that the situation may get worse. Has the issue been resolved for you?
Good morning mmusperf2004 and theaub1,

I’m sorry to hear about the rough idle/smoke issue with each of your ATSs. If you would like to PM me with your VIN, mileage, dealership name, and personal contact information, I would be happy to further discuss your possible options going forward.

Theaub1, I understand that you are in Canada and I would be happy to forward your information to their care team if you PM me with the above requested information.

Have a great day,

Austin J.
Cadillac Customer Care
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