I hear a lot about how much better the Pentastar is compared to the 3.8L. There must be 3.8's with a ton of miles on them by now. Anybody have any serious issues with the older engines? How many miles on yours?

My wife's '13 JK is parked next to my '08 JK and, speaking as a mechanic, I would much rather have the 3.8 to work on. It's a lot more user-friendly with everything out in the open. I changed the serpentine belt on the '08 the other day and I gotta say, if we ever blow the belt off the '13 I think I'm going to scream. Even getting at the spark plugs is more of a chore.
Let's hear your horror stories about both these engines.

 

141,000 kms so far and not a single problem to speak of. I do have a V8 on the brain though, but if I wait till this motor is shot I might be waiting for another 5 years, lol. I have a '10 4dr JK.

 

Not bad at all. A buddy who wrenched at a Chrysler dealer said if ya change that oil every 5000km, the 3.8 will last forever. I guess he was right!

 

50,000 regular oil changes no issue. 2009 jk.

 

88k so far, 2007. It has eaten some oil its whole life, but I just top it off here and there. No issues besides that.

 

Wife has around 140,000 miles on her 07 I have about 35,000 on my 07

 

It must be true that the 3.8 with the cast block is a better engine. More ponies and better milage from the Pentastar but I think the 3.8 is more solid.

 

Just under 59k on my 07

 

Only 49k on mine. Only problem was replacing the water pump.

 

^ good to hear. 08 with 120,000km. Rebuilt at 60km for oil use. Runs like a top and nice and quite on 5W30.

I'm happy to keep driving it as long as I can