96/7 Jeep 4.0 Oil and filter.

[mikeg5]

i owned a 95 or 96 wrangler 5spd with 4.0.. the only issues were leaky rear main seals, computer went out at 130k something miles $800.00, leaked like a mo fo.. other than that it lasted (when i sold it) at 190k miles or so. i regret selling it honestly.. however the 02 GC was a POS!!!!! the brakes sucked, [censored] plastic on the inside, the fan mod went bad, electrical issues, window guide broke, leaky rear main seal gya the list can go on. all before 90k miles.. ill never own another one.. oh the 4x4 transfer case was a PIA! man i can keep going.. they maybe better now but really the early 00's sucked and i am not the only one who says it.. now if i can find a good used 96ish wrangler 4x4 i would buy that. that tranny was top notch, the 4x4 was great and the motor of course is da shizzle.. just find the leaks and plug em up

ill stick with my toyota she gets used but taken care of at 128k miles it has NEVER been in the shop other than regular maintenance.. i love the quality

 

[afoulk]

Only other problem I know of with the 4.0's, other than the rear main seals leaking is the exhaust manifolds cracking. Other than that, they were an awesome engine.

 

[Gary Allan]

Yeah. Ours is "ticking". It took about 140k and 9+ years.

 

[Zaedock]

Originally Posted By: mikeg5
i owned a 95 or 96 wrangler 5spd with 4.0..


It was a '95. There was no '96 model year Wrangler.

 

[DaGr8Tim]

Rather than start a new thread, I figured I'd post on one that pretty much covers my sitution.


At the end of Feb, I bought a 97 Jeep Cherokee 4.0. The odometer showed 248,000, but I think the engine has been opned or replaced. But because I don't have any way to confirm this, I am working from the assumption that the engine does have 248K and if it doesn't that's a bonus. The oil was thin and black, and it had a Mopar filter that looked pretty good. I replaced it with Castrol GTX 10w30 & a wix filter. About 1500 miles, the oil is getting dark and I want to shorten the first few oil change intervals.

When I first changed the oil, I seriously considered running Rotella 15w40 because it seems popular for Jeeps. I think for my 2nd change, I really want to do the 15w40. My question is, is there any downside to doing the 15w40, esp in the summer time. I'm in Columbus, Ohio and it's really starting to warm up for the year.

 

[Gary Allan]

You can run it without worries through the winter if you want. My son did in his 00 in single digit range. Not a peep/squeal/whatever. Now he was pumping glue for a few miles and he may hav spent a few bucks more in fuel in the process.

Keep in mind that the most substantial impact of viscosity is going to be where the differences are the most. That's when the stuff is cold/below op temp. They're the least different at op temp.

 

[440Magnum]

Originally Posted By: DaGr8Tim
Rather than start a new thread, I figured I'd post on one that pretty much covers my sitution.


At the end of Feb, I bought a 97 Jeep Cherokee 4.0. The odometer showed 248,000, but I think the engine has been opned or replaced. But because I don't have any way to confirm this, I am working from the assumption that the engine does have 248K and if it doesn't that's a bonus. The oil was thin and black, and it had a Mopar filter that looked pretty good. I replaced it with Castrol GTX 10w30 & a wix filter. About 1500 miles, the oil is getting dark and I want to shorten the first few oil change intervals.

When I first changed the oil, I seriously considered running Rotella 15w40 because it seems popular for Jeeps. I think for my 2nd change, I really want to do the 15w40. My question is, is there any downside to doing the 15w40, esp in the summer time. I'm in Columbus, Ohio and it's really starting to warm up for the year.


If I'd just picked up a Jeep like that, I'd probably take the time to hook up a mechanical oil pressure gauge to see what's going on- noting idle pressure hot and cold as well as cruising speed (say 2000 RPM) pressure hot and cold. If you're seeing 40-50 hot cruise and no lower than ~10-15 hot idle on a 30- or 40- weight, that engine is in pretty good shape. 248k isn't really all that uncommon for a 4.0, either, although I'd expect it to probably have noticeable cold piston slap and warm valve train noise. Oh wait, *NEW* 4.0s had those...

IF the pressures are good, I wouldn't mess with a 15w40, I'd give it a 5w30 or 5w40. But like Gary said, if you don't mind pumping glue (I like that...) for a few miles on cold mornings, 15w40 will work OK.

 

[DaGr8Tim]

Originally Posted By: 440Magnum
If I'd just picked up a Jeep like that, I'd probably take the time to hook up a mechanical oil pressure gauge to see what's going on- noting idle pressure hot and cold as well as cruising speed (say 2000 RPM) pressure hot and cold. If you're seeing 40-50 hot cruise and no lower than ~10-15 hot idle on a 30- or 40- weight, that engine is in pretty good shape. 248k isn't really all that uncommon for a 4.0, either, although I'd expect it to probably have noticeable cold piston slap and warm valve train noise. Oh wait, *NEW* 4.0s had those...

I've checked the pressure, and it runs 52 while crusing (even at highway speeds), 44 driving around town, and drops down to between 18 & 21 idling at a stop light or idling in park.

From what I've read this is the low side of normal for the engine and par for 4.0's with over 100+.

My worries is to keep it running as long as possible. I wasn't sure if the heavier weight, plus things like the ZDDP would be a bonus.

 

[440Magnum]

Originally Posted By: DaGr8Tim


I've checked the pressure, and it runs 52 while crusing (even at highway speeds), 44 driving around town, and drops down to between 18 & 21 idling at a stop light or idling in park.

From what I've read this is the low side of normal for the engine and par for 4.0's with over 100+.

My worries is to keep it running as long as possible. I wasn't sure if the heavier weight, plus things like the ZDDP would be a bonus.


That's pretty normal and I'd say well within the normal variations among 4.0s. My recommendation for RTS still stands, its got the ZDDP in case you need it, and its built on an superb synthetic base oil that's only slightly more expensive than dino.

 

[Gary Allan]

That was higher than my wife's 4.0 new. It had 42 tops cold, 24 peaked hot, and about 13 hot idle. That's within spec's in the manual. There's a wide variance allowed in the FSM. 75psi is the max, which I figure is the safe limit in the distributor drive. I put in a HV pump. While I like it, it kinda makes choosing a visc more cumbersome.

 

[mstrjon32]

The Cherokees had a real oil pressure gauge, one of few cars made after 1980 that I've driven that did. Moves up and down with the pressure of idle/load, rather than just sitting in the middle all the time.

 

[Greaser]

On the passenger side of the engine,on the block near the front by the coil,are a series of numbers stamped into the block.If you find them they will tell you the year the block/engine was assembled.It's in between number 3 & 4 cylinder.First number is the year,next 2 are the month,the next 2 will be "MX" which stands for"4.0l (242 cid)8.7:1 compression ratio with a multi-point fuel injection system",last 2 digits tell the day it was built.Mine was built in 1999-02-17 day.

 

[440Magnum]

Originally Posted By: mstrjon32
The Cherokees had a real oil pressure gauge, one of few cars made after 1980 that I've driven that did. Moves up and down with the pressure of idle/load, rather than just sitting in the middle all the time.


I've actually seen quite a few with working factory OP gauges, including Cherokees, Durangos, Dakotas, and Rams, and most Jeep models. However, while they all will show the rise and fall of pressure they're not particularly accurate in the actual pressure reading they show. LOTS of discussion board threads out there about how much the gauge reading changes when a sending unit gets replaced, for example. A good mechanical gauge (or even a fairly inexpensive one like a Sunpro) is more accurate than most factory gauges.

 

[Zaedock]

Originally Posted By: 440Magnum
A good mechanical gauge (or even a fairly inexpensive one like a Sunpro) is more accurate than most factory gauges.


Agreed. I run a mechanical in tandem with my factory. There is a difference.

 

[Gary Allan]

I've been lucky with my wife's. The day I installed the HV pump, it read the pump man's relief setting (58lb). It sat right below the 60lb mark at cold start ..and that's where it's always peaked.

but the span really isn't as important as seeing the signal attenuate and retreat from there. I mean, assuming that you're not hearing lifters clacking and whatnot.

 

[440Magnum]

Originally Posted By: Gary Allan
I've been lucky with my wife's. The day I installed the HV pump, it read the pump man's relief setting (58lb). It sat right below the 60lb mark at cold start ..and that's where it's always peaked.

but the span really isn't as important as seeing the signal attenuate and retreat from there. I mean, assuming that you're not hearing lifters clacking and whatnot.


I agree, just having a gauge that moves and behaves consistently so that you can see abnormalities is WAY more important than down-to-the-last PSI accuracy. Its just nice to be aware that your gauge behavior may change quite a bit when you replace a component like the pressure sender, and when discussing pressures with other owners of the same make there may be a big difference in reading even though the real pressure is identical.

 

[Gary Allan]

Quote:
Its just nice to be aware that your gauge behavior may change quite a bit when you replace a component like the pressure sender,


Yes. It's happened enough to always be suspect. It's the first thing I'd hit if something appeared "unright".

Quote:
and when discussing pressures with other owners of the same make there may be a big difference in reading even though the real pressure is identical.


It's a jeep thing. Some still don't understand

 

[mikeg5]

Originally Posted By: afoulk
Only other problem I know of with the 4.0's, other than the rear main seals leaking is the exhaust manifolds cracking. Other than that, they were an awesome engine.


yep totally forgot about that. that happend to both my jeeps. i replaced them with some nice headers

 

[meep]

my 238,000 ZJ did best with Rotella T 5-40 or maxlife 10-30 and 1/2qt PP or syntec 5-20. search the threads. That small bit of 5-20 quieted the valves every time.

I miss the 4.0. alot.

M

 

[DaGr8Tim]

Originally Posted By: meep
my 238,000 ZJ did best with Rotella T 5-40 or maxlife 10-30 and 1/2qt PP or syntec 5-20. search the threads. That small bit of 5-20 quieted the valves every time.

I miss the 4.0. alot.

M


So 5.5 quarts of 10w30 or 5w40, and half a quart of 5w20?