Originally Posted by JIMBOX
Years ago, when the certain 07/08 jeeps started to use a LOTTA OIL-
The trend to move to a more dense/thicker/heavier oil started--now (2012) jeep recommends 5w-30 anyway and the 3.6l v6 has more moving parts, than the 3.8l v6 !
I've used 5w-30 Mobile one since 1200 miles on my '08 JKUR, she doesn't use any oil between changes (once a year) regardless of mileage-
We had one of the 3.8s that burnt a lot of oil and knocked and it was spec'd for 5w-20. However, to keep the powertrane warranty in effect, it never saw any 0/5/10w-30 oil. 30 grade oil may have helped, but it would have voided the warranty if the engine ever did let go.
The question is - did Chrysler ever update the engine to be able to effectively use 5w-20 oils?
Honda and Ford did - and their engines have excellent durability on light oils.
I think the 2013 3.6 specify 5w-20. A few people speculate it's because 5w-20 can move heat away quicker than heavier oils and that a thermo design flaw was causing the ticking issues.