They use 5w20 to cheat a little extra out of the fuel mileage for ratings. I wouldnt use 5w20 in it even if they called for it. More important then the weight of the oil is the additives and class oil you are using. You really want to at minimum use a type 3 lubricant, a good type 4 would be my choice probably because type 5 oils are just too dam expensive and really not needed for a jeep if you are changing on a regular schedule.

 

You can download the latest manual from Jeep online. It may have been updated.

My Jeep: Jeep Owners Service Manuals - 4x4 SUVs, Sports Utility Vehicles, Off Road

 

Hey ordered it new. He had the first one in my town.

 

Mine's a very late 2012 model year (May 31, 2012 build date). Does the oil filler cap on his 3.6 say 5W-20 or 5W-30? I wonder if he somehow wound up with an OM from a 2011, Chrysler made a typo, or Chrysler originally specified 5W-20 and changed to 5W-30 later on for the 2012s?

I do know that Jeep has never apparently updated the iPhone app for 2012 (not like it's that much different, but there are some differences, the auto transmission being one). They only offer a new iPad app now (as far as I can find in the app store), because apparently Jeep is under the impression that everyone slaps an iPad to their steering wheel and nobody uses iPhones anymore.

 

Idk I got to ask him. He has the 3.6 i know that. He got it earlier then most people on this forum. I wonder

 

I have a 2012 JK, and my oil filler cap says 5/30w. I know the 3.6 uses an electronically controlled vane style oil pump, which changes pressure according to engine RPM. I would never use 20w oil in anything, but that is just me. I live in Pennsylvania, and go to a really good dealer for warranty work only. Mine has been been running 10/30w Penzoil platinum plus since my first oil change. Then every 5000 miles when I do my LOF (lube, oil, filter). All my front end parts have been changed to real metal ones, so I do have to grease everything also. I have also never used any engine oil below 10w in any vehicle I have ever own. I just took my 4.0 liter apart to put a stroker kit in it, and i always used 10/40w in the winter and 15/40w in the summer. All the mains looked great. I just use the 10/30w, and Jeep on.

 

In my 2013 manual it says the recommended oil is 5W20, but 5W30 can be used if 5W20 is not available.
I bought my Jeep used with 34k miles so i have no idea what is in there currently, but when my oil change is due, i'll go with Castrol Edge 5w30

Oil by SilverFJ RSM, on Flickr

oil1 by SilverFJ RSM, on Flickr

 

....And my build date is October 2011 ('12 2-door Rubicon). Cap says 5W-30, manual says 5W-30; it's got Mobil1 5W-30 in there now.

 

So my 3.8 cap says 5w-20..... So most everyone is recommending using the higher 30 level so 5w-30?

Sent from my iPad using JK-Forum

 

Ha. I also use 5w-30 in my 2012. Though I don't use Mobil 1 because it does not carry the specified Chrysler MS designation. Penzoil and royal purple synthetics do. I'm not saying Mobil 1 is bad, but it's no better than other oils that do carry the MS cert.