Synthetic in Jeep 4.0 with 130K

[HawkeyeScott]

2001 Cherokee. Owner for 6 years and have put 87K miles on it.

Just changed the oil last night and for the first time I've owned it, she now has full synthetic in her. I've used mostly conventional but have used synblends here and there. Today she woke up with Q Torque and a NapaGold.

I wanted the extended drain this time. And I wanted to switch to 5W-30 in anticipation of maybe spending some time up north this winter. And the only 5W-30 I had was synthetic. That made the decision for me.

So...I guess now is the time I hold my breath and wait for all the consumption and leaks.

 

[Nick R]

That 4.0L is a stout engine, it should work great on that oil.

 

[tomcat27]

it might be a good time to change tranny fluid, xfer case fluid, differentials, coolant - before winter! n unless they changed the design, the 4.0L does have a tendency to leak oil near the oil filter - but its actually only an o-ring on the other side of the oil filter mount/adapter that needs changing. oh... I've had 5 Jeep XJ's....

 

[HawkeyeScott]

Most of the fluids are relatively new. I did the rear diff. this summer and the tranny fluid 8 months ago. Both of those are also synthetic. The transfer case was done 2 years ago, and I've had it in 4WD once since then. But the front diff. and the coolant could use a swap. Good advice.

 

[edvanp]

I just bought a Jeep for my daughter and it has 5w40 M1 Synthetic in it. It also has 171k miles on it. Runs great though! The QS should be a good fill for it for those tough Cackalacky winters you experience.

 

[98dakarM3]

The 4.0L is a very solid motor.

I have owned multiple Jeeps and have become quite a fan of the 4.0L.
Watch for oil leaks out of the rear main, the oil filter adaptor, and valve cover. On one of my Jeeps, it was leaking a few drops on the ground and I discovered that the valve cover bolts were only hand tight!! The leak disappeared after I tightened things up.

The 4.0L is very easy on oil, and I have had great luck with GTX (which i used before discovering BITOG and that there were better values out there) and Pennzoil YB. The engine will be quite happy on a dino oil, but I think I will either run Delvac or Rotella 5w-40 in my next 4.0L. A slightly thicker oil keeps those engines running a bit quieter.

Enjoy your Jeep!

 

[Greaser]

HDEO in the 4.0L tractor motor is my favorite

 

[440Magnum]

Originally Posted By: HawkeyeScott
2001 Cherokee. Owner for 6 years and have put 87K miles on it.

Just changed the oil last night and for the first time I've owned it, she now has full synthetic in her. I've used mostly conventional but have used synblends here and there. Today she woke up with Q Torque and a NapaGold.

I wanted the extended drain this time. And I wanted to switch to 5W-30 in anticipation of maybe spending some time up north this winter. And the only 5W-30 I had was synthetic. That made the decision for me.

So...I guess now is the time I hold my breath and wait for all the consumption and leaks.


I bought my '99 Cherokee 4.0 a year and a half ago with 120k on her. First thing I did was change every fluid she had to synthetic. Still zero leaks, and the Jeep has the lowest oil consumption (no top-off needed on 6k mile OCIs) of any car I own.

FWIW- 4.0 engines do very very well on RTS 5w40. I tend to err on the side of caution because it has a flat-tappet cam. Yes, I know they're not failing by the millions out there so low-phosphorous SM oils are probably OK to use. But given how much that engine likes to lug at low RPM and the flat cam, I figure an HDEO is doubly worth it.

 

[FastSUV]

dino 10w30 HM oil is best choice...or Rotella T-syn but I think the HM oil is best for the 4.0 since it most likely has some seepage...Pennzoil HM is what mine prefers, not sure how cold your winters get, but it might be that 5w30 is better for you, but it gets to 20* here routinely in winter & 10w30 has always worked okay

 

[Silber Igel]

Syn motor oil in a 4.x L engine is way over the top...IMHO.

Having had a 'Four Deuce' six in my '87 Wrangler for 18 years...(now in the caring hands of my best friend...and doing great!!) It's my experience that these motors are not highly stressed and don't need the protection of a full synthetic oil. With a 5, or 5 1/2qt sump, and a 1 qt filter even on a 100F day the oil rarely gets above 220F. These variants of the old Chebby "Stove Bolt Six" are tractor motors. Low rpm 'torque-rs'and any revving over 3000 rpm just converts gas to noise. Syn oils would be a needless excess.

A "SM" rated 'blend'in the recommended grade would be the better choice. More so if you've got cold winters or doing short trips where the oil rarely gets to operating temp. A blend is the economical choice to assure that the oil circulates faster on start-ups and flows better at intermediate temperatures where the engine operates most of the time.

Syn lubes in the manual gearbox, xfer case and diffs is an excellent idea!! There's a [censored] of a lot of drag in all these turning bits when using dino EP90 gear oils. If its a manual tranny, a full syn is the best choice ... no more snagged shifts in freezing weather!!

Cheers!

 

[Gary Allan]

While the basic design hasn't changed (head reconfigured to the more modern 2.5 flow design), the typical driving environment has. Nobody typically used a CJ/YJ as a daily driver long term. The kidneys complain after a while. Other drive train aspects of the shorter wheel base (SWB) offerings also made longer term ownership/usage cumbersome on a consumer (two piece AMC 20 axles - Peugeot BA trans in the YJ - Carter BBD carb's ..vacuum axle engagement ..etc.).

The Chero and TJ installations are far more conducive to daily driving over longer distances. 200k-300k is much more doable in those chassis (chassi?) over the sensible life span of the chassis and therefore you can sensibly take advantage of the benefits of synthetic oils.

 

[Silber Igel]

Never the less.... the 4.x L motors are not highly stressed and today any "SM" oil should do the job. "SM" is "SM" regardless if its dino, blend or synthetic. The advantages of using a full syn in these motors is not clear to me when you can get almost the same cold flow characteristics in a 'blend'.

 

[mikeg5]

Originally Posted By: HawkeyeScott
2001 Cherokee. Owner for 6 years and have put 87K miles on it.

Just changed the oil last night and for the first time I've owned it, she now has full synthetic in her. I've used mostly conventional but have used synblends here and there. Today she woke up with Q Torque and a NapaGold.

I wanted the extended drain this time. And I wanted to switch to 5W-30 in anticipation of maybe spending some time up north this winter. And the only 5W-30 I had was synthetic. That made the decision for me.

So...I guess now is the time I hold my breath and wait for all the consumption and leaks.


that 4.0 is a great great motor. yes she bleeds in different areas on occasions but thats the nature of the beast. use any oil with confidence.

i will warn you, your motor is the LEAST of your worries. keep that tranny fluid CLEAN CLEAN. same with the gear boxes. at that mileage i was having electrical and tranny issues. i had to get rid of it at 120k miles bc it was getting worse. i miss the ride but not the issues that came with that chrystler product.

 

[Gary Allan]

Agreed. It comes down to the difference of one 18 year old motor that was typically serviced every 3month (or whatever) with 20 year evolutions in oils ..or a 1995-2001 Chero who had done any sensible maintenance over 250k. The distinction is merely in how often you should change the oil. With one there's little sense to a synthetic ..the other you can sensibly take advantage of the benefits in terms of longevity ..with bonus features that a conventional (except for the broad evolutions that occurred in over 40 years that this engine has been around) cannot provide.

Most of the CJ/YJ's I've seen are either semi retired into occasional use .. trail hacked ..or sitting as some dedicated snow plow. A Chero can actually be sent to the junkyard from old age with a fully functional engine. TJ's are unique in that there's CJ like demand for them in salvage in spite of far greater numbers being produced over fewer years.

 

[Silber Igel]

I can assure you Gary, that 18 Y.O. motor was not 'over maintained.' It did receive OCs about every 5K even with '80's and '90s oil.

Correct, there's probably no sense in using synthetic with 3k OCIs. On the other hand, SM oils will provide excellent service to 5K and beyond. As to a 'bonus' feature provided by a synthetic.. that's a surprise. Regardless of its provenance an oil that meets, or exceeds, a specification be it, API, ILSAC, ACEA, SAE, FORD they all perform to the same standard. And that's what they have to do to have the 'approval.' Probably the only difference between dino, blend and syn oils is in their ability to transition between cold, cool, warm and hot temperatures whilst maintaining pumpablity and flowabilty... with a slight edge going to blends and synthetics. Even dino 5W20s pump and flow well and stay in grade. Otherwise, they're all equal.... because that's the performance standard.

The only way to tell if you are "over maintaining" with too frequent OCs would be to pull a sample and check the remaining TBN. You need 'just enough' TBN, and no more,to get you to the longest OCI .

 

[caravanmike]

thats funny the cherokee xj has the aw4 automatic and is reported to be one of the most stout auto transmissions around. did you know the aw4 is the same transmission in your 2002 tacoma (A340E)?

 

[FastSUV]

Originally Posted By: caravanmike
thats funny the cherokee xj has the aw4 automatic and is reported to be one of the most stout auto transmissions around. did you know the aw4 is the same transmission in your 2002 tacoma (A340E)?



tell me the significance of running the 10w40 in your 4.0 up there in Ohio??? I have one here and use 10w30 but have wondered if since this is a 'tractor' motor if the thicker is better?

 

[Gary Allan]

Quote:
I can assure you Gary, that 18 Y.O. motor was not 'over maintained.' It did receive OCs about every 5K even with '80's and '90s oil.


Nor did I state or imply that you did. I don't think anyone here ..in any vehicle that I can think of, is using an 18 year old engine as a front line daily driver. That is, you don't have 500k miles on it. That usually means that it WAS a front line driver at one time ..and then retired to lower mileage demands. Since you have personally kept track of it, I'd say that it's also not sold and treated like a beater and/or trail hacked (not an insult-just a mod). I'd say that it sees limited mileage now too.

btw- how has it been used for the 2nd half of its life? How many miles does it have on it now ..and how many miles did yo put on it when you bought it?

This usually means that maintenance is done on a time weighted schedule instead of a mileage weighted schedule. Most CJ's that were mod'd for trail use were already 20 years old and yet the mileage was around 120k or less. 100k would be torture in a CJ over a shorter span of time. Anyone with normal needs would use another vehicle for any type of lengthy daily drive for ride/economy and a number of other reasons. It should be similar with a YJ.

Quote:
On the other hand, SM oils will provide excellent service to 5K and beyond.


No argument. The "beyond" part is hard for many, including yourself apparently, to breach.

Quote:
Regardless of its provenance an oil that meets, or exceeds, a specification be it, API, ILSAC, ACEA, SAE


Well, let's just grab on to ILSAC here. You can latch on to that if you wish. Keep in mind that there are many tests that are PASS FAIL ..and that anyone displaying the GF-4 badge passed. The lowest additized SuperTech ..to the most expensive M1. What is the invisible elephant in the room (apparently) is that some PASS MUCH BETTER THAN OTHERS.



We're getting nowhere here. You did fine using SG-SM oils.

 

[hounddog]

Is that Q Torque? a REAL synthetic or one of those by name only?

 

[Greaser]

OK.. LETS MAKE IT SIMPLE..with the Jeep 4.0L engine you can use ANY oil and filter just change it once in a while and drive it for 300,000 miles..by the way my TJ is my daily driver since 2001 and 230,000km of happy commuting so far and the wifey drives the XJ to work 289,000km thus far