It's been a while since I re-addressed this problem. All you people should go through and read this posting thoroughly. It is NOT NORMAL for a hydraulic lifter engine to tic after sitting overnight.

Just to update everybody; my engine has had the driver's side head replaced and now has just over 3000 miles with no tic whatsoever. Chrysler will fix your Jeeps, its called a warranty; the dealer may jerk you around. If this happens call Chrysler directly and complain.

By reading these threads you will see many people have did just that. It's truly amazing what you can learn if you spend some time and READ.

From the pentastar website

Cylinder head failures
In June 2012, dealers reported that some engines had premature cylinder head failures, usually on cylinder 2. The problem seems rare considering the number of these engines produced, and nobody was stranded by the problem, which made itself known through the "check engine" light. Customers were generally given loaner cars while the issue was being resolved, though in some cases there was a considerable delay as Chrysler engineers sought root causes and an effective cure. A fix was engineered and entered production in June, and by mid-July, the backlog of replacement heads was being addressed, and all new heads were of the new design.

Thanks. Very interesting. My JKUR was stalled in "final inspection" at the end of May. No known cause, customer service would only speculate. I finally took delivery in mid-June. Wonder if I have the newly engineered head.

Is there a way to check which JK's have the pentastar with the re-engineered heads? Can a dealer use a vin number to find out this information?

I've obtained info from another Jeep forum. The part number for the original factory head and the part number for the re-engineered replacement heads. Having the part numbers may enable those who have to have a new head installed, verify that it is actually a re-engineered head not just a new head but same part #.

Replacement Head: RL141353AB
Original Head: RL141353AA

This article really puts all the prior build date questions to rest.

If your Jeep was delivered before this date then you could have issues.

Where is this part number found on the head ?

I don't know. But, for those who have them already installed at the dealer, their invoice should have the part number. The rest of us may be SOL until we get the CEL.

Interesting -- I have a 5/30/12 build date on my Rubi (almost like yours except that I have an auto and 3.73 rear). I'd bet that if you have the new head then I probably do, too. Since I didn't order mine (lot buy), I don't know if it was held for the same reasons as yours, but I sure am curious.

It would be nice to know how difficult it would be to located the part number on the head.