JK Question: 3.6 or 3.8?
- Thread starter John Rooks
- Start date
Since this is a TJ forum, you'd be better off asking this question on a JK/U forum 
But, since you asked, the 3.8 was 2007-2011. And the 3.6 is 2012-Now.
Of course, the 3.6 is the better engine between the 2.
But, since you asked, the 3.8 was 2007-2011. And the 3.6 is 2012-Now.
Of course, the 3.6 is the better engine between the 2.
OP
I realize that, but the people who own TJ's seem to be more mechanically inclined than the jk owners. They seem to be more inclined to pay to have their work done. This forum everybody seems to be more helpful and knowledgeable. My friends thinking about going with the JK but I told him is a lot of bad things about both engines in certain years so I thought I'd ask you guys.Since this is a TJ forum, you'd be better off asking this question on a JK/U forum
But, since you asked, the 3.8 was 2007-2011. And the 3.6 is 2012-Now.
Of course, the 3.6 is the better engine between the 2.
The 3.6 was introduced in 2012 and is a MUCH better engine than the 3.8. It's not the 4.0, but hell, you can't have everything
In 2012, there were some head problems.
There isn't anything really wrong with the 3.8. It's been around for years. Think of all those mini vans that traveled across the country. It just wan't the right engine for the Wrangler.
For reliability, I'd say the 3.8 is the winner. Just because it's been around for so long. The 3.6 hasn't been around THAT long yet.
3.6 Pentastar was introduced in 2012 in the JK/JKU. Early models had cylinder head issues and there was a recall.
The older 3.8 was a minivan engine and under-powered IMHO.
The older 3.8 was a minivan engine and under-powered IMHO.
The 3.8 is a piece of garbage... Honestly. All I ever read about it are horror stories, how it's severely underpowered, etc. I wouldn't even touch any JK that had a 3.8 engine in it, not at all. The 3.6 Pentastar was a massive improvement. Ideally you want a 2013+ 3.6 though, as the 2012 models had cylinder head issues.
Having had both, the 3.6, as stated above, is definitely the superior choice (post early 2012). I didn't have any issues with the 3.8, but once I drove the 3.6, the difference was amazing. It did, however, have a lot to do with the new automatic transmission introduced along with the 3.6 in 2012. The combination was worlds ahead of the 3.8 & 42RLE combo. My 3.8 was with a standard transmission, so the lack of power wasn't as noticeable. The lag due to drive-by-wire on the early 3.8 was definitely noticeable.
The wife herds a 2012 JKU through the woods. Here's what i know about the 3.8 & 3.6 engines.
The 3.8 is not the right engine for the JK/U. It works, it's reliable and there are a bunch of them out there. The torque and power bands don't match the transmission when used in a Jeep. If things like that aggravate you, avoid the 3.8.
The 3.6 Pentastar engine works in the JK. It needs more RPM than the 4.0 to work. It's not a big deal.
Some big deals are:
2012 - might develop head issues.
2012 - 2014 might eat the oil anti-drainback valve. Dorman has a $20 kit available to fix that. If you have a 3.6 it's worth having one in the tool box JIC.
All years might leak in the rain. Both the soft top and the hard top had occasional issues with quality control. It happens often enough that Chrysler has two repair kits and an extensive service bulletin about it.
All years might develop electrical gremlins. Those are just a huge pain in the ass to deal with.
If you off road the rig, and it's a JKU, you might eat a front drive shaft or the Dana 30.
If it's a JKU with an automatic, and you load it up and drive the snot out of it, you might fry the transmission.
On the other hand, if you avoid all of the above, they are actually really nice Wranglers and an improvement over the TJ in a lot of ways for a lot of people. Just not me. I like my TJ SE. My wife likes her 2012 JKU. I modify and / or repair both.
The 3.8 is not the right engine for the JK/U. It works, it's reliable and there are a bunch of them out there. The torque and power bands don't match the transmission when used in a Jeep. If things like that aggravate you, avoid the 3.8.
The 3.6 Pentastar engine works in the JK. It needs more RPM than the 4.0 to work. It's not a big deal.
Some big deals are:
2012 - might develop head issues.
2012 - 2014 might eat the oil anti-drainback valve. Dorman has a $20 kit available to fix that. If you have a 3.6 it's worth having one in the tool box JIC.
All years might leak in the rain. Both the soft top and the hard top had occasional issues with quality control. It happens often enough that Chrysler has two repair kits and an extensive service bulletin about it.
All years might develop electrical gremlins. Those are just a huge pain in the ass to deal with.
If you off road the rig, and it's a JKU, you might eat a front drive shaft or the Dana 30.
If it's a JKU with an automatic, and you load it up and drive the snot out of it, you might fry the transmission.
On the other hand, if you avoid all of the above, they are actually really nice Wranglers and an improvement over the TJ in a lot of ways for a lot of people. Just not me. I like my TJ SE. My wife likes her 2012 JKU. I modify and / or repair both.
Can't add much to what's already been said, except a 2011 JKU owned by a friend of my daughters, and driven like a baby, never offroaded, is in the shop getting a new transmission. I think it's a common enough problem because the 3.8 is not well-matched to the transmission. I'll tell you something, if I was having to replace a 6 year old transmission, I would not be a happy camper!
Don't avoid the JKU. Just choose wisely. They really are a nice enough rig that's it's worth getting one. Notice that I said might in most of my reply. It's a risk, not a given. Chrysler built tens of thousands of the JK/U and the majority of them are happily motoring down the highway and trail. They are nice enough rigs that you want to find out why somebody is selling one though, if you are looking to buy a used one.
The wife's JKU has displayed none of the faults listed above, except for the top leaking. Hers has a malformed top. It was cut and sewn together incorrectly. Since it doesn't fit right, it leaks. A new Bestop will fix that. It's worth it to us because less than 4% of JKU's came with half doors like she has. The rest of the rig has been extremely reliable and just rocks for what we use it for. Don't fear the JK/U, just be aware.
Know exctly what ya' mean. I'm Jeep poor at the moment. (Well, that and all the other hunting, fishing and backwoods gear laying around the house)
My son has a 2012 (3.6) I am aware of early head issues, his has not had problem also Chrysler has extended warranty for this to 150000 miles
From my experience driving the 3.6 I would defiantly go that direction more H.P then 3.8 . The jeep is 1000lbs heaver then the T.J it needs it, the motor has been out 5+ years now if there were on going major issues they would of shown up by now
From my experience driving the 3.6 I would defiantly go that direction more H.P then 3.8 . The jeep is 1000lbs heaver then the T.J it needs it, the motor has been out 5+ years now if there were on going major issues they would of shown up by now
IMHO, the biggest shortcoming of the JK is that you're paying 40k for a Rubicon model, but for that price, shouldn't it have a Hemi V8 in it? Ummm... yeah... it should.
I'm sorry, but unless you've got a ton of money to spend, 40k is A LOT of money. That's 1/3 of a house in some places.
I'm sorry, but unless you've got a ton of money to spend, 40k is A LOT of money. That's 1/3 of a house in some places.
And barely a down payment in others. (cough, cough) JK/U's are popular. The Rubicon in all it's JK flavors even more so. Anything with wheels on it is just flat out expensive these days. Especially anything worth driving. You are going to pay a premium to drive a cool rig like a JK/UR.
Sure, a Hemi would be nice in the JK, but remember that the original MB only had something like 36 HP. It got around just fine. The 3.6 pushes the JKs down the road great for all intents and purposes. Heck, we blew across South Dakota at 10 over the speed limit with me and two women and all their luggage in our JKU without any drama what-so-ever. Over hill and dale, never impeding traffic in the slightest. Got pretty decent mileage in the process. You could melt 35's to the asphalt with a Hemi, but I'm a little past that appealing to me.
Bottom line is you got to pay to play. If nobody wanted a Wrangler, TJ's would be going for $4,000 and down and JK's would be going for $18,000 and down. But a lot of people do want a Wrangler and are willing to pay for them.