4.0L engine rant...

[lautinjr]

tjkj2002 I'm sorry but how can you say that 4.0l engine is bad because it leaks oil?? We all know that. It's not a big deal. That's why you check your oil level. It has a trac record of going over 300,000 miles. You can't denie this. It's a good engine period.

As for the 4slow... I have a friend at work who says he beat out a sports car with a 4.0 Comanche

Any response to that?

Ya did the Miata he raced have a misfire or something?

 

[tjkj2002]

tjkj2002 I'm sorry but how can you say that 4.0l engine is bad because it leaks oil?? We all know that. It's not a big deal. That's why you check your oil level. It has a trac record of going over 300,000 miles. You can't denie this. It's a good engine period.

As for the 4slow... I have a friend at work who says he beat out a sports car with a 4.0 Comanche

Any response to that?

Problem is most never check there oil and work in a shop long enough and you see the trends.Sorry will never own a 4slow ever again.Cheaper in the long run.I beat sports cars everyday with my 3.7 in a 6000lbs KJ,just means there not trying to race(niether I'm I).

 

[jmnetus]

Have to say... my 4.0L XJ definitely felt a bit zippier from cold stop than my new 3.7L KJ. But the 4.0 did leak oil like crazy no matter what we did to it - can't deny that one

 

[tommudd]

The 4.0s had their share of issues from the get go
But people were convinced they were the best engine ever made
But most are also ones who never work on them just take em to a shop and say here fix whatever it is
I owned 3 of them and while they did go up into the over 200,000 mile range, but so did my 302 - 351 Fords, 350 GMs etc.
They are like the Harley Shovelheads as long as you can keep them running they are fine

 

[HoosierJeeper]

I had a WJ with the 4.0. It performed good, liked the lowend power, got better MPG than the 3.7, and left the engine bay open enough to work on. I traded the WJ in at 47k/3 years old, so I never had an issue with the engine.

 

[tommudd]

mmmm I never got that god of mileage out of the 4.0s best maybe 17-18 and that was it on a trip, KJ does way better on the average
4.0s do have some low end torgue over the 3.7s but overall I like the 3.7s better. No leaks on mine at 172,000 , no cracked exhaust, plugs etc are no harder to swap out so overall its 3.7 for the win

 

[jmnetus]

Huh. YMMV on the 4.0L I guess then. On my final trip from Utah to North Idaho, I got about 23mpg on it - far better than the 19 or so I'm doing in my KJ.

 

[rockymountain]

Huh. YMMV on the 4.0L I guess then. On my final trip from Utah to North Idaho, I got about 23mpg on it - far better than the 19 or so I'm doing in my KJ.

at stock height, if you're only getting 19 on the highway something is wrong. Or you're driving 80MPH or more...

The 4.0's torque was great...

 

[tommudd]

3.7s have just as much torgue as the 4.0s , just comes in at a different RPM is all. With proper gearing its all in how you drive it. None of the 4.0s came close to my highway mileage in the KJ

But then it all is if you like potato's or potatoes
sodas or pop
ying or yang
everyone likes what they like
:shrug:arty52:arty52:

 

[Marlon_JB2]

The 3.7L/Mitsubishi rumor is still going around, I see! LOL That's hilarious, I swear I thought that died years ago.

I was wrong.

The sole reason why *I* can't stand the 4.0L?
The sounds it makes while running, make it sound sloppy and cheap. Can't stand the sound of the exhaust either.

 

[rockymountain]

The sole reason why *I* can't stand the 4.0L?
The sounds it makes while running, make it sound sloppy and cheap. Can't stand the sound of the exhaust either.

x2

 

[seabass1858]

Heres the bottom line IMHO, take care of your car, don't forget to change the oil, check all fluids. Would I get another 4 Slow, in a xj ABSOLUTELY, as mentioned before I got 310k miles out of mine all original drive line and 170k were mine, the 95 XJ was well taken care of and used synthetic oil since birth. I only changed the rear main seal because I saw one drop of oil coming from there and when I see an oil leak, I am one to flip out cause I have OCD and while I was under there I changed the oil pump for good measures because it had 250k at the time. I got 20MPG with it with 31s and 16-17 with the 33s. I will not put down the 4.0L because it had a lopy idle and the sound of no lobe separation in the cam. I didnt care at the time. It went with me all over the east coast and mid west and never let me stranded on the side of the road, I did loose the original muffler and tail pipe somewhere in Missouri which I ordered a walker cat back from rock-auto for 120$ other than that I just put new main seal, oil pan gasket, oil pump (for good measures), valve cover gasket, oil filter gasket, regular tune up, radiator because a tornado blew a large tree limb into my radiator, new grille, water pump (for good measures). Did what I needed it to do, got where I needed to go, provided reliable transportation for the family during my absence, I have no complaints. Total repairs 350-400$ after 110k of my own miles, cost of jeep $1200.


PS the AW4 is an awesome automatic transmission no complaints there ether.

 

[tjkj2002]

I had a WJ with the 4.0. It performed good, liked the lowend power, got better MPG than the 3.7, and left the engine bay open enough to work on. I traded the WJ in at 47k/3 years old, so I never had an issue with the engine.

I also had a '01 WJ with the 4slow,worst engine I have ever owned.I'd rather have a GM 305 V8.It couldn't get out of it's own way if it wanted to,and yes it was in top running condition as you all should know by now I'm super **** about maintenance.I get better mpg's now with my SFA KJ then that WJ ever did and can get over 65mph in a headwind with my KJ.Best theing I ever did was trade it in for the KJ.

 

[dude1116]

at stock height, if you're only getting 19 on the highway something is wrong. Or you're driving 80MPH or more...

The 4.0's torque was great...

I'm grabbing about 19/20 as well with quite a bit of highway driving. Got the plugs done a while ago. I could use another plug job soon, I'm sure. But I can't imagine getting much more than what I'm getting now. Sometimes I get 21/22 if I'm going on longer highway trips. But that's about it.

 

[J-Thompson]

Just drove the TJ for the first time in 5 weeks
Is it s speed demon? No it is a Jeep
Can is get 33's to chirp/spin on dry pavement?
Yup from a dead stop
And remember that it is locked ,auto and 3.73's
But the KJ could bearly do that with 245/75's and
Open diff.
Yeah the 4.0 has torque
and I noticed that when I got on it the mechanical
fan makes it sound like a rocket taking off which
means I am wasting lots of power turning that thing

To the "I don't like the 4.0 because it makes noise"
Sell your Jeep and buy a Honda
You are not worthy

 

[Marlon_JB2]

Nobody complained about the 4.0L making noise.
There were complaints about the TYPES of noises it makes.
Don't put words in people's mouths.

With that said, I'm sure people also complain about the noises the 3.7L makes, a few don't like that dang fuel injector ticking.

Now the AW4... yeah, uh, I'll agree. Great transmission!

 

[rockymountain]

Going out on a limb here but isn't a TJ about 1000 lbs lighter than a KJ. As far as get up and grunt you can't say anything unless you have a KJ with the 45rfe.

Sure, take a 4.0 that get almost all its torque from 1500 rpms and up yeah you'll have yourself a fun time. There is absolutely no comparison between a KJ and a TJ.

I could do try donuts in my 4 ****** 86 mustang with 4 on the floor. Shit engine, but fun as hell.

 

[k99jk99j]

here is one with 612,000 miles original 4.0L

Link:
Jan Richey

 

[J-Thompson]

Wow
"the type of noise"
Really? This is the best we got?
The only noises I hear in my Jeeps are/were
1) the sound of M/T's slapping pavement
and/or
2) the sound of wind whipping through an open window
or open top or doors removed
Sorry guys but the "type of noise" thing is very
weak

As to the KJ not chirping tires
It out weighed the TJ by about 500# give or take
it was much faster ,no question
It did have the 45RFE
None of that was my point
My point is/was to the fact that at 1500RPM the
4.0 is making more than enough torque to move
even a WK up most any hill
In the newer Jeeps this is not the case
They need much more RPM to make torque
Thus they end up with much more speed
Off road speed = damage
damage = bad ,even more on a new Jeep
Take it how you want it is an undeniable fact
And don't bother posting how the 3.8 or 3.6 makes
more torque and blah blah blah......
They don't do it at 1500 RPM
You can not almost idle a JK up a hill
I can climb with just bearly touching the gas
thus they need more RPM
thus off road the 4.0 is better
And lest not get into what they can do when you
"stroke" them

 

[tjkj2002]

Wow
"the type of noise"
Really? This is the best we got?
The only noises I hear in my Jeeps are/were
1) the sound of M/T's slapping pavement
and/or
2) the sound of wind whipping through an open window
or open top or doors removed
Sorry guys but the "type of noise" thing is very
weak

As to the KJ not chirping tires
It out weighed the TJ by about 500# give or take
it was much faster ,no question
It did have the 45RFE
None of that was my point
My point is/was to the fact that at 1500RPM the
4.0 is making more than enough torque to move
even a WK up most any hill
In the newer Jeeps this is not the case
They need much more RPM to make torque
Thus they end up with much more speed
Off road speed = damage
damage = bad ,even more on a new Jeep
Take it how you want it is an undeniable fact
And don't bother posting how the 3.8 or 3.6 makes
more torque and blah blah blah......
They don't do it at 1500 RPM
You can not almost idle a JK up a hill
I can climb with just bearly touching the gas
thus they need more RPM
thus off road the 4.0 is better
And lest not get into what they can do when you
"stroke" them

When my KJ was "almost" stock I could do burnouts at will with 225/75 MT/R's,I can still chirp the tires with 35x12.15's and weighs 6000lbs.I can also idle up and over just about everything.