Best Long Drain Synthetic for Jeep 4.0L InLine ?

[UltrafanUK]

If you read Oil 101, or the Blackstone Lab article, there is no such thing as a best oil or best oil change interval.
Just look around Wallymart for the major brands on special, pull out your internet thingy and look up the oil guide or finder page of the chosen oil company web site. They will list which oil makes them the biggest profit first, although Liqui Moly will list all their oils that have the correct API or Acea certs and SAE range.

When you drive to Wallyworld to start your stash, try not to leave the owners handbook behind, as that will list the SAE ranges and API certs.
If you still have an extended warranty, just look for the fully approved (The oil that is supposed to be used by the stealer) oil.

9 or 10K miles might well be OK for an OCI, but if you want a realiable answer try getting a few UOA's with TBN done.

 

[901Memphis]

Originally Posted By: Bandito440
Rotella T6 5w-40
Mobil 1 10w-40 HM
Mobil 1 0w-40
Mobil 1 5w-40 TDT


I concur, with a preference to M1 HM 10w40 in his climate.

 

[UltrafanUK]

Originally Posted By: Bandito440
Rotella T6 5w-40
Mobil 1 10w-40 HM
Mobil 1 0w-40
Mobil 1 5w-40 TDT


I don't think the OP mentioned oil leaks and if you use an HM oil in a good engine it will swell the seals up slightly (Not as much as a stop leak), which will increase the pressure on the associated shaft. Seal conditioners in normal major brand oils do not do that.
TDT might have the wrong spec if it was designed for use in DPF afflicted diesels.

Shell Rot 5w40 is kind of thick for a petrol job unless it's in a hot desert area towing a 2 horse box or monster caravan on a regular basis with a K&N air filter.

So that leaves M1 0w40, which is fairly close to some thicker 0w30's like Casteroil Hedge!

 

[jayg]

Originally Posted By: DoubleWasp
I'd skip the 40's. It made the engine in my JGC feel more sluggish, and hit my fuel economy a bit.



In Florida, in any temps you'd experience, I don't see how you would feel sluggishness between 30wts and 40wts or notice more than a fraction of percent difference in fuel economy. I know I know, how can I argue with your feelings? I just never experienced any of that when I lived in GA.


If the OP HAS to run 9k changes, I'd run a syn hm 10w40 and keep an eye on the level. I think i'd just change it every 5-6k on an engine with such an old design. I change mine once a year at nearly 5k every spring in my LC with a similarly designed 4.2 I6 and I use 10w40.

 

[Chris142]

We are not concerned about sluggish but protecting an abused engine.

 

[Kuato]

Originally Posted By: demarpaint
Originally Posted By: Chris142
I'll 2nd leaky seals. Don't go long with that engine. Mine chewed up torco in 4400 miles!


Add me to that list. I wouldn't chance a 9-10,000 OCI, nor recommend it w/o a UOA. Blanket statements w/o data to back it up can often lead to problems when it comes to extended drain intervals.


FWIW, I ran my '04 4.0 up to 10k intervals with Amsoil, showed plenty of TBN remaining; Blackstone said try 12k.

 

[jayg]

Originally Posted By: Kuato
Originally Posted By: demarpaint
Originally Posted By: Chris142
I'll 2nd leaky seals. Don't go long with that engine. Mine chewed up torco in 4400 miles!


Add me to that list. I wouldn't chance a 9-10,000 OCI, nor recommend it w/o a UOA. Blanket statements w/o data to back it up can often lead to problems when it comes to extended drain intervals.


FWIW, I ran my '04 4.0 up to 10k intervals with Amsoil, showed plenty of TBN remaining; Blackstone said try 12k.


Just depends on the usage. Stop and go short trips , I wouldnt push 10k.


All highway commute? Sure, although I'd reconsider a Jeep for that job.

 

[Kuato]

Originally Posted By: jayg



All highway commute? Sure, although I'd reconsider a Jeep for that job.


Mine was 80% highway; Grand Cherokee is a comfy highway cruiser....older Wranglers, not so much.

 

[mtxjohn]

Amsoil, hands down

 

[BrocLuno]

I've never heard of half this malarkey ... It's a Jeep. It's square box fighting it's way through the wind with big tires and a fully exposed undercarriage. It was not bought for fuel economy. And anyone that can feel the difference in this rig from 10w30 to 5W-40 is living in La-La land.

Rotella T-6 5W-40 is thickish, but M1 0W-40 is OK ... They're both 40's at op temp.

And Rotella is actually a bit on the thin side of real 40's - like HDEO 15w40's etc. I know because I have switched some of the ranch trucks to T-6 in lieu of Delo400 15w40 and seen a couple of PSI oil pressure drop at hot idle. Jumps right back up to the relief valve setting as soon as you spin the motor up some.

But this is a Rubicon. So that's a fairly new'ish Jeep. It's not a CJ5 or something. If the motor is tight at all (under 100,000 miles), it can live all day, any day on xW-30 and be happy. So what's best xW-30 for 9,000 miles ... I'd guess Pennz Ultra would be somewhere near the top of the list.

But, I'd just run Napa Synthetic 0w30 and a good oversized filter if you can fit one... That's to gain a bit of total lubricant volume and for the extra filter area to carry it out to 9,000 easily. The total volume of oil is the thing that will help keep the TBN in the reasonable range. If you had a 8 quart system, it could go longer than a 5 qt system. Just more oil to absorb fuel dilution, combustion by-products, etc.

Rubicon's are nice, but that I-6 has been around for decades. There is nothing special going on here. Keep it full of reasonable oil and it'll be fine

 

[Kuato]

Originally Posted By: BrocLuno
I've never heard of half this malarkey ... It's a Jeep. It's square box fighting its way through the wind with big tires and a fully exposed undercarriage. It was not bought for fuel economy. And anyone that can feel the difference in this rig from 10w30 to 5W-40 is living in La-La land.

...

If you had a 8 quart system, it could go longer than a 5 qt system. Just more oil to absorb fuel dilution, combustion by-products, etc.

...

Rubicons are nice, but that I-6 has been around for decades. There is nothing special going on here. Keep it full of reasonable oil and it'll be fine

**

No need to be angry!

It's a 6 quart system, OM says 6000 miles IIRC, to reiterate - went 10k in mine.

Agree 100% that any good 30 weight will be fine, but OP asked about going longer because he doesn't see the vehicle very often. This strongly indicates an extended drain oil. PU may be up to the job, Amsoil SS and M1 EP are definitely up to it, but see my previous post about M1 in this particular engine.



** fixed your apostrophes.

 

[DoubleWasp]

The data was recorded using hand calculations of fuel economy over 12k miles.

Disliking data does not make it any less true.

After more than 100k miles, I am very in tune with this truck and engine. Yes, it definitely felt more sluggish, in Florida heat.

Beyond that, I am only one of several people who has reported this on this forum alone.

What a coincidence that I feel sluggishness and document a loss in fuel economy at the same time.

A request was made, and I offered information. Take it or leave it.

I have used thicker than spec oil in plenty of my vehicles to great effect. This application is not one of them.

Do I know, or is their any data that a 40 is going to protect a 4.0 any better at all? Zero. The best 4.0 UOA's posted here have all been 10/30.

Did I get better UOA's with RT6? No. Is my engine still kicking at 260+k miles without constant 40 usage? Amazingly it is. No leaks, no excess blowby, and no funny noises. Imagine that!

But this is America, and you can do whatever you want with your vehicle, including lying to yourself about 40 making it more durable.

 

[BrocLuno]

I'm not angry - I'm having trouble with the M1 and Amsoil fan boys touting their fav's w/o any concrete proof that they will do any better than Pennz or even Napa Syn ...

And UltraFanUK saying one xW-40 is to thick and then recommending another xW-40 is nuts...

My recommendation was inline with the above xW-30 and drive on

I know the OP thinks this is an abused engine, but I'm not convinced it is. It goes a long time between changes, but it's running modern oils ... So where's the abuse?

 

[ChrisD46]

OP here - jeep is mainly used as a commuter vehicle to work in a suburban environment with about 5% off road use. No leaks - Rubicon is the last year the 4.0L in line four was offered (what ever year that is) before switching to the crysler 6 cylinder . *What about the extended drain Mobil 1 , any fans ?

 

[Kuato]

Originally Posted By: BrocLuno
I'm not angry - I'm having trouble with the M1 and Amsoil fan boys touting their fav's w/o any concrete proof that they will do any better than Pennz or even Napa Syn ...

And UltraFanUK saying one xW-40 is to thick and then recommending another xW-40 is nuts...

My recommendation was inline with the above xW-30 and drive on

I know the OP thinks this is an abused engine, but I'm not convinced it is. It goes a long time between changes, but it's running modern oils ... So where's the abuse?

Not touting Amsoil as much as relating my experience with using it for an extended drain in the same engine. That's relevant. I agree though, just coming on and saying "use XX oil" without anything to back it up causes me trouble as well. I couldn't speak for Pennzoil or Napa Syn since I didn't test them....however I DID test ST Syn at 5k and it was fine at that distance, but I wouldn't take it much further so didn't think it worth mentioning for OP's situation.

LOL agree...UnltrFanUK says don't use 40 and use 40 in the same sentence. ...

 

[jayg]

Originally Posted By: DoubleWasp
The data was recorded using hand calculations of fuel economy over 12k miles.

Disliking data does not make it any less true.

After more than 100k miles, I am very in tune with this truck and engine. Yes, it definitely felt more sluggish, in Florida heat.

Beyond that, I am only one of several people who has reported this on this forum alone.

What a coincidence that I feel sluggishness and document a loss in fuel economy at the same time.

A request was made, and I offered information. Take it or leave it.

I have used thicker than spec oil in plenty of my vehicles to great effect. This application is not one of them.

Do I know, or is their any data that a 40 is going to protect a 4.0 any better at all? Zero. The best 4.0 UOA's posted here have all been 10/30.

Did I get better UOA's with RT6? No. Is my engine still kicking at 260+k miles without constant 40 usage? Amazingly it is. No leaks, no excess blowby, and no funny noises. Imagine that!

But this is America, and you can do whatever you want with your vehicle, including lying to yourself about 40 making it more durable.



So in the Florida heat, when the two oils are the closest in properties (as opposed to extreme cold) you could feel the sluggishness of the oil? I don't doubt it felt sluggish but maybe more because of ambient IAT than OCIs between 30/40 wts. The hotter the oil gets, the thinner it gets and at temp they should be not much different .

 

[DoubleWasp]

I hate to be "that guy" talking about the butt dyno, but I was in no way predisposed toward any expectation of the results I got. I even ignored the feeling at first, until it became very obvious my fuel economy had taken a hit as well. Even then, I chalked it up to it being just about anything else at all. After all, I have never felt or recorded any difference between grades in any other engine when using a heavier spec oil.

The first point of taking any of this seriously at all was when I switched back to 10/30. All of a sudden my Jeep felt the way I always remembered it being. Then, my fuel economy ticked back up to within a tenth of the consistent recorded fuel economy I had documented before switching to RT6.

Even then, I wasn't 100% convinced. The nail in the coffin for me was talking to other 4.0 owners I know who encountered the same results, and then finding the same experiences both on this forum and others. Hard for me to doubt it at this point.

But even that is not what made me leave 40 behind. I was on the same side of the fence as the others who feel "It's a Jeep. Who gives a ____ about fuel economy and speed.". What made me leave it alone was the plain and simple fact that I have never found any evidence at all that a 40 does any more for a 4.0 than waxing the valve cover. I've done thing with my JGC that nobody would ever advise be done with a Jeep. I've used it to drag a 14,000 lb. forklift up a grade several times. Had her skidding back and forth for 15 minutes while dragging the same forklift out of the mud. Done the same thing for plenty of of my buddies out in the Everglades. Know what the impact has been on my UOA's? Nada. A good 10/30 will deliver 100 out of 100 under the most ridiculous abuse in Florida heat.

 

[Kuato]

Originally Posted By: DoubleWasp
I hate to be "that guy" talking about the butt dyno, but I was in no way predisposed toward any expectation of the results I got. I even ignored the feeling at first, until it became very obvious my fuel economy had taken a hit as well. Even then, I chalked it up to it being just about anything else at all. After all, I have never felt or recorded any difference between grades in any other engine when using a heavier spec oil.

The first point of taking any of this seriously at all was when I switched back to 10/30. All of a sudden my Jeep felt the way I always remembered it being. Then, my fuel economy ticked back up to within a tenth of the consistent recorded fuel economy I had documented before switching to RT6.

Even then, I wasn't 100% convinced. The nail in the coffin for me was talking to other 4.0 owners I know who encountered the same results, and then finding the same experiences both on this forum and others. Hard for me to doubt it at this point.

But even that is not what made me leave 40 behind. I was on the same side of the fence as the others who feel "It's a Jeep. Who gives a ____ about fuel economy and speed.". What made me leave it alone was the plain and simple fact that I have never found any evidence at all that a 40 does any more for a 4.0 than waxing the valve cover. I've done thing with my JGC that nobody would ever advise be done with a Jeep. I've used it to drag a 14,000 lb. forklift up a grade several times. Had her skidding back and forth for 15 minutes while dragging the same forklift out of the mud. Done the same thing for plenty of of my buddies out in the Everglades. Know what the impact has been on my UOA's? Nada. A good 10/30 will deliver 100 out of 100 under the most ridiculous abuse in Florida heat.


It's not your fault that other people aren't as perceptive about their vehicle's behavior as you are. Being serious here, if you are paying attention you notice stuff; and having a corrolation with lower fuel efficiency backs it up.

 

[Greg L]

About the OP, +1 for the Mobil 10w40 HM

 

[4WD]

Prompted me to look up that 10w40 HM ... strong stuff right there ...