Jeep Garage  - Jeep Forum banner

2012 Jeep GC 3.6L notorious problem

101K views 84 replies 45 participants last post by  Diddy3323 
#1 ·
Hey guys, just hired a Jeep tech at my dealer i work at. Asked him about my 2012 Jeep Grand Cherokee 3.6L V6 and any problems with them that they normally see on a daily basis. He told me that most of the 2012 Jeep GC with the 3.6L V6 will throw a check engine light around 25,000 miles due to a known defect in the left head. The problem is a burnt valve in cylinder 4 and will most likely be replaced under warranty. Just letting you 2012 owners out there know of possible problems in the future when you rack up the milage. I am at 20,000 miles so I'm just waiting for it to happen to me. The Check engine light code is P0304 and its cylinder 4 misfire most likely caused by that valve that burns up. :mad: Good thing for warranties!
 
#2 ·
I'm dealing with the engine light issue and based on everything I've read and discussed with folks, it typically happens much sooner then 25k. Mine started around 9k and has been on and off for the last 5k with one trip to dealer during that time in which they did a camshaft sensor fix/cleaning process. I'm now at 16k and it is on again. After talking to 3 different dealers, all of them have stated that they have only had a few 3.6L come through with the head issue and is not widespread issue. However, I'd say majority of the '11 and 12s have under 20k, so time will tell if it is a big widespread issue.

-
 
#7 ·
I'm dealing with the engine light issue and based on everything I've read and discussed with folks, it typically happens much sooner then 25k. Mine started around 9k and has been on and off for the last 5k with one trip to dealer during that time in which they did a camshaft sensor fix/cleaning process. I'm now at 16k and it is on again. After talking to 3 different dealers, all of them have stated that they have only had a few 3.6L come through with the head issue and is not widespread issue. However, I'd say majority of the '11 and 12s have under 20k, so time will tell if it is a big widespread issue.

-
This is a different issue. The head problem creates a misfire code.
 
#3 ·
From what I've been Told, the 3.6L pentastar motor which is used in most new dodges and chrysler and all v6 jeeps now, definitely has a problem with a defect in the head from being built at plant and I've been told that they are repairing around 5 a week at my local jeep for 2012 grand Cherokee and other models with same motor. As I was told by the keep techs and my local jeep dealer "this issue is no secret, it's going to happen if it hasn't already and will be fixed under warrenty most likely."
 
#4 ·
interesting...is it more of 2012 issue then 2011? My dealer claims they've sold over 100 3.6L and have only a few come back with the head issue over the last 18mos.
 
#6 ·
Its seems most of the ones I have read about have been 2011 models which would stand to reason since those would have more miles. They have built over a million of these engines now if they all had the problem as suggested Jeeps would be lined up around the block at the dealer service departments. So I really doubt thats the case.
 
#10 ·
My 2011 JGC V6 with only 9,000 miles is in the shop as we speak waiting for a new cylinder head. I was told it will take over a month due to redesign and backlog. Started with CEL coming on, then it started to blink andn then started to beep and blink. I was told my mechanic I should have pulled over and called for a tow to the nearest dealer.

Looks like this has the potential of a major recall?????
 
#11 ·
Just curious if this issue has been fixed at some point in the build process? Is there a build date point that the 3.6L was updated or revised so it does not have this potential issue? Im just curious as I took delivery of my 2012 Overland V6 in March (cant remember the actual build date off the top of my head).
 
#12 ·
Sounds like a recall item to me! If that many of them are predicted to go bad I sure would be pissed if my 3.6 breaks down at me 1000 miles from home with onle 20 some thousand miles on it! My 2012 was built in December of 2011 so if there was a fix I doubt mine has it.
 
#15 ·
Think of it like this, its a brand new engine, it going to take years to get every bug out which there will still be bugs even then lol. Your power train is 5 year 100,000 miles. Your butt is covered and whatever happens, happens. And if it happens, brand new parts :)
 
#18 ·
A friend of mine was shopping Wranglers and held off his purchase due to this. There as a revised head casting designed and placed into production for late June 2012. Not all heads are affected and from the water cooler discussions with finite element analysis types they believe a casting issue at the limits of design tolerance is the cause. These are NOT Chrysler people, just an eclectic few auto enthusiast engineers whom discuss these kinds of things over beers on the weekend while I make mental notes. That there was only a left head redesign placed into production makes me believe that they over-engineered the affected area to account for something (head wall thickness? coolant passage flow adjusted?). It could be a myriad of things. The good news is that I have a Hemi, my friend has a Hemi (and thanks me now), and not all Pentastars are affected.
 
#20 ·
I have over 44k miles on my 2011 GC, it was built in June 2010 so it's about as early as they come. I've not had any problems with the engine at all, it runs nice and smooth.

Only issues I've had was with the sucky Michelin tires that got noisy (finally took a nail in the sidewall at 33k and replaced with Firestone Destination LE's) and with the transfer case producing a moaning noise at very low speeds - a fluid replacement helped, but didn't fully cure, that problem.

Other than that I've just tried to stay up to date with any TSB's that related to software updates, those cured all of the various transmission driveability issues that were common early on.
 
#21 ·
This exact issue is comnig up on my 2011 GC 3.6L V6 right now. First CEL came on (blinking and beeping at me) in March.. dealer replaced entire electric manifold (they obviously didnt know what was going on).. CEL came on again last month, took it in- local service tech noticed high pressure on coil in cylinder 4, replaced coil and sparks- CEL went off; still had abnormal system readings- CEL came on next day (today).. just saw this post. I'll tell him about it!!! he was resorting to looking into PCM replacement!! yikes... i'm 2nd owner; no warranty unfortunately....
 
#23 ·
Out 2012 JGC bought exactly a year ago is now in the shop after having a #2 cyl misfire code come up 3 times. the first time was about at 15.000 miles it now has about 22k on it.
The first 2 times I brought it in they said "oh it needed to be re-flashed for an update".
This last time I threw a fit and told them they better have a bag of parts for me when I pick it up as it was BS. They then called me and said we need to ship it to our sister dealership as we don't have a tech with the correct level of training on hand to troubleshoot it.wtf?
Now he tells me if it is the head issue like they are starting to see more of at the sister dealership it will be a minimum of 2 weeks out..
It is what it is..
 
#26 ·
I purchased a 2012 Jeep GC 3.6L in January 2012. Since then I have had a huge problem with the check engine. The first time the car had a very noticeable failure, it seemed like it was about to turn off. Since then I have had to take it about 10 times because of the check engine light. The Service Department at my Dealer tells me it just needed computer updates. This makes no sense to me. Now recently the gas cap light turned on even though I am 100% sure I closed it correctly. The Check Engine light has usually turned back on not even 24 hours after I have picked it up from service. I don't know a thing about cars and am afraid they are taking advantage about the fact. I am looking for information to see if anyone else has had a problem similar to mine and how they resolved it, or any advice. Thank you
 
#28 ·
Only way to know is with an OBD-II code scanner. Codes P030x (x=0-6 for pentatar) indicates misfires. The actual number can be determined by a good scanner. Code meanings can be found on;ine.

If you do not know what all of this means it is best that you take to a mechanic you trust.

That said constantly recurring CEL lights even after taking it in for service usually means that they have not fixed the problem.
 
#29 · (Edited)
There is a TSB on the check engine/gas cap MIL. Mine started going off multiple times at about 6 months/6000 miles. A trip to the dealer for a flash and I have not had a single issue with either since.

Make sure your dealer has actually been doing the TSB instructions and not "winging it" by just resetting the MIL's. If so, they will just keep coming back. Best luck.

http://wk2jeeps.com/tsb/tsb_wk2_1805011.pdf
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top