What's the best weight to use for winter time where the average temp is anywhere from 25*F to 40*F? Is 5W-30 okay? BTW, I use Mobile 1 synthetic.

 

You should use whatever is listed in your owner's manual. Seriously. It will depend on if you have the 3.8 or 3.6, and also what model year. The oil weights are different between the 3.8, and different model years of the 3.6. 25-40F isn't truly cold weather, so the oil weight listed in the manual will be fine. Be sure to adhere to whatever spec is recommended, i.e. Chrysler MS-6395, etc, if you want Chrysler to honor warranty repairs on the engine if any troubles arise.

 

It'll be hard to find Chrysler spec oil in Germany.
The european specs for the JK 3.8 are: "ACEA C3" and MB (Mercedes Benz) spec "MB 229.31" or "MB 229.51".

 

Got it...thanks, guys.

Sent from my Jeep.