I just rolled over 100k in my 3.8. 40k of those were on 35's and stock 4.1 gears, and 60k of them on 37's with 5.13 gears. The only issues I've had were intake manifold oil leak, oil pan leak, valve cover leaks and an exhaust manifold leak. The oil leaks I fixed in a day with $60 worth of gaskets and a tube of RTV.

The engine starts and runs great. I burn about 1qt oil every 1200 miles or so. Has done this since brand new, but I would not hesitate to drive it anywhere anytime. I carry a 5qt container of Mobile 1 in the back and check the oil every time I hit about 1k miles on my trip meter. I would not mess with any performance mods unless you count a snorkel and gears of course. The motor is like a tractor, not powerful but very dependable just watch the oil level. I anticipate hitting at least 200k on mine!

 

260,000klm on my 08.. no issues and it has been on 35s and 37s all its life...
you will find that only people who have problems post to complain. Those that have had no issues seldom say a word unless asked.

 

I have 111k miles on my 07, its been an offroad only rig most of its life. It was on 35's till 100K then 37's for the last 11K. I dealt with cracked exhaust manifolds and a drippy oil pan that were warranty repaired, I have currently what looks like a slight intake manifold oil leak but its hard to tell as its around the water pump... Other than that it has enough power to pull my 1500lb pop up, up the big hills in southern Ca.

 

****, I wish my JK only had 28k miles. I'm sitting at 155k miles and still dropping money into it without worry of the engine.

 

150k without issues. As far as "performance", I have run a high flow air filter (with a used oil analysis that says it's not allowing too much dirt into the oil), a 'tune' with the superchips, and now a snorkel for those "just in case" moments.

It's been a great motor, not sure where you're getting the poor reviews but I'm certainly envious of your low mileage. I hit 28k my first year.

 

90k on our 2011 with no issues.

 

I'm still shaking my head on his 2008 JK having 28K miles on it and worrying about high mileage engine concerns. At that rate, he'll finally hit 100K miles in 30 years and likely have another 100K or more of engine life to go.

 

My 3.8 has been reliable.

Not a V8 by any means but it's powerful enough to push my 35s around town. I'm sitting at 113k and she isn't showing signs o dying yet.

When she goes 150k, I'll be right where the LS or hemi will be saved for. Drinks a little oil, nothing crazy, but runs and starts every damn time.

 

How'd you like to swap engines with me? At 202,000 miles, mine has been proven. Okay, replacing the fuel injectors right now because they started making a lot of noise, and there was the cracked exhaust manifold--likely caused by cold water hitting the thin metal during river fording--and the intake manifold gasket that was leaking, causing occasional engine roughness, but it's been pretty strong otherwise. A proven product, so how about it?

I'm just kidding, of course, but the problems noted above are fact. :-)

 

Jeep sat in storage for 7 1/2 years without being started once while I was deployed. Got home in Aug. changed oil, battery, took it off blocks aired up tires and drove to Phoenix and back without an issue.

Its now back in storage and won't be started again until May so we will see how it goes. Just wanting to get a little more horsepower out of it. Im running the EVO bolt on, 5:13's in D44's and 37's, ball joints and a few other small mods. Standard transmission. Have opened up the airbag with a KN but thats about it as far as engine mods....not much.
It does ok off road for east coast wheeling but would enjoy a little more power through the mud holes and on my drive through the Smokies and black Mountains when I roll through there.

Thats kind of what i was hoping to find out regarding the post.