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Topic Review (Newest First)
05-19-2013 11:31 AM
jklarry the guys on here bashing the 3.8 because "Chrysler" built it are the same guys that will use the oil that "Chrysler" tells them to because they cannot or will not learn to think for themselves. from day one I have used syn. oil and a different weight than what the dealer told me to use, my Jeep does NOT use oil and I change it once a year. the Jeep is happy and I am happy, 45,000 and going strong
05-19-2013 09:31 AM
michiganadam Have 27000 miles on mine, ive owned it since 25000. Hasnt burned a drop of oilsince i bought it. Its not as powerful as a jeep ought to be though.
05-19-2013 06:26 AM
Rtone1583 Kinda funny how the past always looks better through the lens of nostalgia.

Back in the mid 90's I worked at a Jeep dealer and seem to remember the venerable I-6 having a problem with incorrect cylinder bore sizes from the factory. Basically they would pass muster for a little bit but once some miles were put on them and the rings properly seated they started burning oil at low miles because the rings couldn't maitain the proper tolerances. Factory fix was to install slightly larger pistons and rings.
05-19-2013 03:02 AM
Miser It's a good proven reliable engine! It gets a bad rap, because Chrysler engineering did a poor job of matching the HP and torque of the engine to the weight ratio that it is expected to move down the road. The automatic trans and factory gearing married to it also doesn't help.
A few of them burn some oil, which is no big deal. Just check it and add when needed!
05-18-2013 09:22 PM
JTPhoto JK Considering of the 1,000,000 JK that have been built since 2007, just over 800,000 are 3.8. This is not even taken into account how many hundreds of thousands that are in other vehicles. I'd say they are very reliable. We have 3...
05-18-2013 08:40 PM
conwaymac Over 132k and runs great. Does not burn oil either. Like most engines, oil changes and being CLEAN when doing it etc...they should last an awfully long time.
05-18-2013 07:33 PM
Rogerg Im almost at 80k on my JK and no problems with the motor other than it sucks oil.The only other engine I owned and never gave me grief is the 5.3 Vortec.

Its very true that people would only post about the negatives on the 3.8 and if the ones that are satisfied posted, it would outnumber the negative for sure.
05-18-2013 06:28 PM
CG3 3.8 = is a fine engine.... I mean.... it wasn't built for a sports car... and not really underpowered as much as the jeeps with 3.8's are under - geared.....
05-18-2013 06:12 PM
SilverSport
Quote:
Originally Posted by KC_Hawker View Post
I keep seeing on this forum that everyone should avoid the 3.8 at all costs. I have one but I am now only @ 36K miles. I have had no issues. I drove the 3.6 before buying this one used. I liked the extra power of the 3.6 and now after having the 3.8 I can see the transmission issues on a grade or headwind at speed but...

How many people have had their own 3.8 fail due to something they didnt cause? Are these things failing left and right? OR is it more an underpower issue?
Answer: No, not unreliable.
05-18-2013 12:50 PM
Dogzilla I'm on my third 3.8.......Zero problems.
05-17-2013 11:00 PM
LewdDude Agreed! the 4.0L I6 was excellent! Kinda wish they were still using it after my 3.8L failed. Fingers now crossed on my 3.6L, but I have the lifetime extensive coverage from chrysler so I am not too worried anymore as it will never run out!!!

My son was upset when the old tonka Jk broke down as he wanted it when he turns 16... he isn't gonna get this one either!!! LOL No worries, dad will find him a good jeep when the time comes...



Quote:
Originally Posted by jp2611 View Post
IMO (which isn't worth much really) it is gonna be hard for any motor to match up to the 4.0 I6....now before everyone starts saying biased......remember that the 4.0 was ORIGINALLY designed in the min '50s for AMC/ Rambler and was "Improved on" for 50 years before it was put in the TJ's...so yeah it is gonna be hard for any motor to beat that much of a learning curve/ improvement right out of the box......A lot of people have no issues with the 3.8....and I still have my fingers crossed on the 3.6 in our '12 JK...but I feel pretty confident with my TJ with 160K+ and no real issues and none motor related.

Part of the reason I never want to sell the TJ even a replacement motor is not too costly...and lots of parts to MOD with!!!
05-17-2013 10:45 PM
gr8fulKID I have 115k on my 08 without issues and im pretty sure it will last well above 300k
05-17-2013 05:00 PM
jp2611 IMO (which isn't worth much really) it is gonna be hard for any motor to match up to the 4.0 I6....now before everyone starts saying biased......remember that the 4.0 was ORIGINALLY designed in the min '50s for AMC/ Rambler and was "Improved on" for 50 years before it was put in the TJ's...so yeah it is gonna be hard for any motor to beat that much of a learning curve/ improvement right out of the box......A lot of people have no issues with the 3.8....and I still have my fingers crossed on the 3.6 in our '12 JK...but I feel pretty confident with my TJ with 160K+ and no real issues and none motor related.

Part of the reason I never want to sell the TJ even a replacement motor is not too costly...and lots of parts to MOD with!!!
05-17-2013 04:40 PM
LewdDude
Quote:
Originally Posted by RemoJK View Post
What'd you do
to cause it??? lol Nothing. Cylinder 4 and 6 had a clog of sorts and the bearings were shot. Started burning oil since the last oil change. Had all my service records but I was still outside my warranty
05-17-2013 04:14 PM
Old Dogger
Quote:
Originally Posted by rics1997 View Post
Actually the 4.0 and the 3.8 had very similar numbers. They just put the 3.8 in a heavier vehicle especially the JKU with a bad transmission/gearing combo. If you put a 3.8 in a TJ with a TJ transmission you probably wouldn't notice the difference. And the 3.8 was a very durable engine.
I agree with you on the weight scenario.
If you were to weigh a TJ, verses a JKU, My guess would be 500 to 600 lbs. more. That in it's self would make the engine sluggish and seam under powered. And yes the wrong transmission used and gearing was not to the optimum for that application.
The JK/JKU also being wider with more wind resistance is another negative, but a minor one!
When the Engineers married that combination, well they must have been drinking too much Budweiser.......
05-17-2013 03:56 PM
BLK2012 3.8's are great...had 70,000 trouble free on mine...no oil issues either..
05-17-2013 03:16 PM
the Kolector Saying that "all" 3.8s are unreliable because they are from Chrysler is equivalent to saying that since there are bad people out there our maker is unreliable. You can't lump all of 1 product in the junk category because there are issues, there will be various issues with any product, especially ones as complex as a vehicle. But that's just my .02
05-17-2013 03:06 PM
jkjeeper06
Quote:
Originally Posted by Blastek View Post

I guess it's how you look at it. You make a good point. Most engines used to burn oil. Now most engines do not burn oil. Tolerances are better now. Anything the owner has to do that is beyond normal, for example, topping up oil at every fillup (read - not checking), is not reliable in my mind. It's not necessarily detrimental, but it's something that you shouldn't have to do to keep a modern engine going. If you stop that additional effort, you'll probably end up with a lump of iron with a hole in the side.

Same thing with the 3.6. If you don't replace the heads every 30k, you'll be SOL.
0.02
I understand what you're saying, and I see your point but...

The degree at which engines burn oil is what matters ALL(read all) engines burn at least a little oil in the winter(real winters with white stuff) because with the heating/ cooling and expanding and contracting you get little gaps that a tiny bit of oil squeaks thru and burns. It's usually only the first few revs but it adds up over time.

The distance from the top of the save zone to the bottom on the dipstick is about a qt on the 3.8. So burning 1/2 a qt per oil change is still in the safe zone and wouldn't be detrimental. You'd have to burn over a qt for it to leave the safe zone.

Now if someone says they burn 3/4 qt per oil change is that really bad? They'd never have to add oil. I'd consider everything up to and including 1qt per 5-6000 miles essentially not burning oil. I do a few ounces because I like it topped off to dilute any dirtiness but even if I didn't, I'd be in the safe zone
05-17-2013 02:29 PM
WatchThis!
Quote:
Originally Posted by pkmcd99 View Post
on another note..... if mine ever fails, Im lining up a 5.3 chevy conversion.
I heard that. And I am doing a 6.0 one day. We just put a 6.0 in my best friends buggy. Put a Mast Motor Sports cam, one piece push rods, and swaped springs. Also using the Mast tune and ECMU(lucky for us they are right down the street). The motor cost 1300 bucks and came from a wrecked 09 2500 with 8500 miles on it and is now puting out close to 500hp. The whole build was 9 grand with a new slightly built tranny and drive line mods.

HAHA. Not sure how reliably it is yet though.
05-17-2013 02:20 PM
rics1997
Quote:
Originally Posted by Old Dogger View Post
Wrangler engines, are they reliable?
The word reliable is in the eye of the beholder! Different opinions as to what justifies acceptable reliability.

4.0 in the TJ is the best of the best, just a great durable engine! A opinion.
3.8 in the JK/JKU, proven to be a good engine, but underpowered and some burn oil. A opinion.
3.6 in the JK/JKU, the verdict is still out............No opinion at this time!
Actually the 4.0 and the 3.8 had very similar numbers. They just put the 3.8 in a heavier vehicle especially the JKU with a bad transmission/gearing combo. If you put a 3.8 in a TJ with a TJ transmission you probably wouldn't notice the difference. And the 3.8 was a very durable engine.
05-17-2013 02:19 PM
pkmcd99 on another note..... if mine ever fails, Im lining up a 5.3 chevy conversion.
05-17-2013 02:15 PM
pkmcd99 Personal experiences can be in favor or against about anything. In general, with my experience my 3.8 has been awesome. Zero problems. Keep in mind it is mechanical and man made and can eventually fail like any motor.
05-17-2013 02:10 PM
WatchThis!
Quote:
Originally Posted by scottmphoto View Post
My friend's 3.8 died (threw a bearing) at 50k. He had to spend $4+k on a new engine.
Statements like this is also something we have to think about also...

Say you have 1000 people with any kind of product and 1 of them had one of said product fail. Now lets say this 1 person is acquainted with 100 of the 1000 people that have the same product.

If we where to poll all 1000 people odds are we would have close to 100 people that said they didn't like it because they knew someone who had one that failed. Then you have people who knew the guy who knew the guy who knew the guy that had a failer,this could lead to 400 or 500 bad reviews easy. Of course these are all made up numbers but to me I think this mind set explains the clames of failers for any product that are blow out of proportion on forums.
05-17-2013 02:02 PM
Old Dogger Wrangler engines, are they reliable?
The word reliable is in the eye of the beholder! Different opinions as to what justifies acceptable reliability.

4.0 in the TJ is the best of the best, just a great durable engine! A opinion.
3.8 in the JK/JKU, proven to be a good engine, but underpowered and some burn oil. A opinion.
3.6 in the JK/JKU, the verdict is still out............No opinion at this time!
05-17-2013 01:48 PM
Miser
Quote:
Originally Posted by jkjeeper06 View Post
But that would imply that all or most 3.8's burn oil or that all or most pentastars tick when in reality the vast majority don't.

The reason you read about it so much is that ppl log onto forums to solve problems, not to say how their jeeps are normal and don't burn oil or tick
X2, Very well said!
05-17-2013 01:43 PM
n00g7
Quote:
Originally Posted by scottmphoto View Post
My friend's 3.8 died (threw a bearing) at 50k. He had to spend $4+k on a new engine.

I know it sounds dramatic to say a motor "threw" something, but unless bearing failure resulted in this, nothing was thrown.
05-17-2013 01:25 PM
Blastek
Quote:
Originally Posted by WatchThis! View Post
Good point and I see the logic behind your thoughts. Let me ask you this though. Chevy LS motors and the Chevy TBI 350 (one of the most reliable gas motors ever) are prone to burning oil from time to time, does that mean they all are also unreliable?
I guess it's how you look at it. You make a good point. Most engines used to burn oil. Now most engines do not burn oil. Tolerances are better now. Anything the owner has to do that is beyond normal, for example, topping up oil at every fillup (read - not checking), is not reliable in my mind. It's not necessarily detrimental, but it's something that you shouldn't have to do to keep a modern engine going. If you stop that additional effort, you'll probably end up with a lump of iron with a hole in the side.

Same thing with the 3.6. If you don't replace the heads every 30k, you'll be SOL.
0.02
05-17-2013 01:05 PM
scottmphoto My friend's 3.8 died (threw a bearing) at 50k. He had to spend $4+k on a new engine.
05-17-2013 01:05 PM
WatchThis!
Quote:
Originally Posted by Blastek View Post

Good points. But IMHO, most people log into forums because they are vehicle enthusiasts. A few bother to create an account to ask a question and leave. The vast majority of people don't have a clue about their vehicle and probably don't know how to use the internet. That doesn't mean they don't have problems.

The amount of cases you read online is a reasonable indicator that these problems are prevalent across the board. Otherwise, Jeep would not have their legal department make claims about normal oil consumption. Nor would they redesign a part multiple times and struggle to meet a 500/week demand on head replacements if it was not common.

I've read more than enough cases of oil burning and head replacements to be confident (in my mind) that these are issues that speak to the reliability of the engines.
Good point and I see the logic behind your thoughts. Let me ask you this though. Chevy LS motors and the Chevy TBI 350 (one of the most reliable gas motors ever) are prone to burning oil from time to time, does that mean they all are also unreliable?
05-17-2013 12:58 PM
Blastek
Quote:
Originally Posted by jkjeeper06 View Post
But that would imply that all or most 3.8's burn oil or that all or most pentastars tick when in reality the vast majority don't.

The reason you read about it so much is that ppl log onto forums to solve problems, not to say how their jeeps are normal and don't burn oil or tick
Good points. But IMHO, most people log into forums because they are vehicle enthusiasts. A few bother to create an account to ask a question and leave. The vast majority of people don't have a clue about their vehicle and probably don't know how to use the internet. That doesn't mean they don't have problems.

The amount of cases you read online is a reasonable indicator that these problems are prevalent across the board. Otherwise, Jeep would not have their legal department make claims about normal oil consumption. Nor would they redesign a part multiple times and struggle to meet a 500/week demand on head replacements if it was not common.

I've read more than enough cases of oil burning and head replacements to be confident (in my mind) that these are issues that speak to the reliability of the engines.
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