2012 Jeep Wrangler Long Term Road Test

Edmunds.comEdmunds.com Member, Administrator, Moderator Posts: 10,315
edited May 2016 in Jeep
2012 Jeep Wrangler Long Term Road Test

Our 2012 Jeep Wrangler went in for dealer Service with a Check Engine Light and came out with a new Cylinder Head on its Pentastar V6, replaced under Warranty.

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  • lmyers92123lmyers92123 Member Posts: 21
    Don't sweat the head replacement. Within the Wrangler (and Pentastar) community this has been a known issue. Some valve guides and seats failed resulting in the compression loss. It is almost entirely the left head with a P302 or P206 error. The original heads were suffixed -AA and went into production through about May of last year with an -AB head short lived for a few months afterwards. Current release (that you got) would be the -AC head and I haven't heard of any -AC failures. I've had 2 heads replaced and currently have the -AC head. Most dealer are on top of this so the quick turn around is not unusual.
  • firstwagonfirstwagon Member Posts: 0
    I'd sweat a bit if I still had the original heads and was nearing the end of the warranty.
  • lmyers92123lmyers92123 Member Posts: 21
    Understandable in that scenario. It's covered under the 5 yr/100K warranty and the greatest mileage I have seen before failure was under 20K. I'm pretty sure if you have an issue it would appear before 100K. On above post I meant to type P306 not P206. Often associated with the failure is a ticking but keep in mind the injectors tick normally. It should be pretty distinct between the left and right side of the engine. You may also note some rough idling and reduced mpg's. The dealer will sometimes update the flash to try and address this but everyone I heard of always gets a new head shortly there after. Some dealers comp a rental vehicle and if you get the blank stare call customer care, ask for a case number and a vehicle. BTW, it won't leave you stranded after the check light appears. You should be able to get out of the mountains or desert and back to a dealer without a problem. All the above is based on my experience and yours may be different.
  • jku2012jku2012 Member Posts: 2
    This is a very common issue with the new Pentastars. Seems to be worse in the Wranglers than the other vehicles. They've gone through a few head designs in the past year to correct the problem. My JKU just threw the same code this morning. Jeepers have been following the issue since it started cropping up about 1 year ago in the new 2012's. It is all over most forums.
  • jku2012jku2012 Member Posts: 2
    I have 23,000 miles, and the first CEL came on today.
  • buff4buff4 Member Posts: 1
    I have a 2012 jeep wrangler unlimited rubicon with 8884 miles on it. A week ago the check engine light came on and I noticed the engine seemed a bit weaker and smelled stronger than normal and it seemed that the throttle response was... well... different. I took it in to my dealer and a day later I had it back. They had found code p0300 and the misfire monitor found misfires on #2 and #6 cylinders. They performed a leak down test and found 55% in #2 and 67% in #6.
    They replaced the left side cylinder head and the car was running fine when I hopped into it and I will also say my milage went way up, I was getting around 11 mpg before, actually ever since I bought the car, now it's around 18.

    Anyways, that doesn't leave me feeling too good about my car, was planning on keeping it but now I think that is a bad idea. I look forward to hearing if anyone else has had a similar problem.
  • bessie3bessie3 Member Posts: 1
    Just got bit by the check engine light. Took it in late last night. Today the service adviser called and said that I needed to replace the cylinder head. Unfortunately, the jeep won't be ready until 04/09/13.
  • hollywoodbbhollywoodbb Member Posts: 1
    I have 2012 Jeep Wrangler check Engine light came on, trip to dealership, need a new cylinder head. So annoyed and worried about future problems. Sounds like a lot of people are having this issue. What has jeep said about it? I am at 25,000 miles it just seems so new to be having serious issues like this.
  • bluedragon114bluedragon114 Member Posts: 1
    I have a 2011 Dodge Avenger 3.6L that just hit 90,000 miles. I first noticed a ticking around 87,000 miles (or 6 months ago). Oddly, it's become louder, especially at idle, and low acceleration. It's not constant though, as it will tick then it will stop then tick some more. Worse in reverse. Taking to a dealership Monday. Thank goodness for the 10 yr 150K Mile warranty Dodge offers cuz I just passed my 5 year powertrain warranty a few days ago...
  • roaddawg27roaddawg27 Member Posts: 1
    I have a 2012 JKUR in the shop today with 77,000 and P0018 (cam shaft sensor) and a P0300 (multiple cylinder misfire 2,4,6).
  • grittsygrittsy Member Posts: 1
    I believe this warranty has been extended by Jeep to 10 years or 200000 kilometres for 2012 Jeep Wranglers built in 2012 before July 25 now. I am in the process of getting mine done as we speak
  • reel_travelerreel_traveler Member Posts: 1
    Mine is a 2015 Wrangler with 74K miles, threw the P0306 code over the weekend along with the engine misses. Figured the plugs needed replacing anyway and why not save the $ for parts, so did that plus one of the coils. BTW, getting the plenum off was a bloody knuckle surprise to expose the left cylinder bank! Not complicated, but time consuming... Engine ran fine for 5 miles (code disappeared) then re-appeared along with engine misses at various acceleration angles. I'm sure the head is leaking down so scheduled my appt with dealer. Just to be safe, has anyone heard ANY stories of this not being covered at no cost prior to 100K miles? I love this engine when it works, hoping this is a simple fix and off to 200K miles. Thanks.
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