2004 Rubicon Oil

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Sorry to bring up an old topic, but i have not seen many recent posts and things change with technology. should be an easy question for all of you oil enthusiasts, I have an 04 Rucicon that is my toy. It gets about 3000 miles per year on. Mostly sits in garage. I currently run Amsoil Sig series 10/30
I have been reading about the M1 Delvac 5/40 as being an excellent choice. I only change oil once per year, Is there any better choices for my situation of barely driving that would better fit the flat tappet engine? Or stick with the Amsoil?
 
That old, and I mean OLD design 4.0 straight six engine, loves a 40 weight oil. I would run any of the synthetic 5W40 heavy duty diesel/gas oils, such as Delo or Rotella.

Your car called for API certified oil meeting SM. If that's important to you, just make sure the back of the bottle says SM, or the superseded SN. Some of the the dual rated oils have been removing the gas SM/SN ratings.

If the Jeep gets driven on the highway only, then a 30 weight would be fine. If it sees a lot of idle time (like on trails), then a 40 weight would be better. Id just run a 40 weight anyways, due to these engines running well on them, and being a 40 year old engine design.
 
Any old 10w30 would work fine. My 4.0L sits a lot, only 3,000 miles a year or so.

If you're gonna drive it in the freezing cold, use a 5w30.
 
Premium full syn for 3K - um, I'd prolly go 2 years on a change ...

You are good on Delvac if you want ... But the Amsoil can certainly go a lot longer, and it's good oil
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Lots of good oils out there. Most any of the Euro spec 0W-30's or 0W-40's would be up to the task. Take your pick. You are certainly not beating on the oil. That motor is not hard on oil
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I have a 2005 Rubi .....for many years I ran 15w-40 Rotella about 2 years ago I switched to a 5w-30 synthetic.

I change oil every 5k or which is about once a year.
 
Why are you guys recommending a diesel oil for a gasoline Jeep engine ?
A diesel oil will have soot dispersants that aren't required for this application.
 
If you're only getting 3k a year why are you wasting money on synthetic? I'd stick either regular Delvac or Rotella 15W-40 in there and change it yearly if it were me. Doesn't the 4.0 still run off a tappet cam instead of a roller? If so, it'll appreciate the extra zinc in the HDEO's over the Amsoil for better wear characteristics. I use Rotella 15W-40 in all my old tappet engines and they love it.
 
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0W40 Castrol Edge is great in a 4.0L Rubicon - but maintaining my son's jeep at 10K mile OCI's .
 
I guess my post didn't originally go through.

I like Edge 10w40, but I try to buy it on sale.

My Jeep seems to run quieter on 10w40's. Haven't tried a 15w40, but I will soon.
 
Originally Posted By: Merkava_4
Why are you guys recommending a diesel oil for a gasoline Jeep engine ?
A diesel oil will have soot dispersants that aren't required for this application.


17000 post and still clueless.
 
I am in the same situation as you. 2003 Rubicon with about 3,000 miles a year. I drive it mostly in the winter when the roads are bad and not yet plowed. It is garage kept. It has had Pennzoil since day one. The first seven years when it had the factory warranty the dealer put in the yellow bottle 10w-30. Now I change the oil and filter myself with Pennzoil Ultra Platinum 10w-30. I use the Mopar oil filter. The owner's manual specified 10w-30 so that is what I have used. The oil analysis has been excellent. The powertrain has never had a repair. As a matter of fact, in 14+ years it has only had two repairs of any kind: a rear track bar was replaced (damaged in off-roading) and the passenger front seat belt retractor recliner failed. It has been a great vehicle to own.
 
Originally Posted By: bubbatime
17000 post and still clueless.


Since I have more than one post, it's posts, not "post." Now you tell me who's clueless.
 
Originally Posted By: Merkava_4
Why are you guys recommending a diesel oil for a gasoline Jeep engine ?
A diesel oil will have soot dispersants that aren't required for this application.


Mostly it's fleet oil and the old Jeep 4.0 loves the stuff
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Originally Posted By: BrocLuno
Mostly it's fleet oil and the old Jeep 4.0 loves the stuff
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Oh OK -- if the engine seems to like it then there's no issue I guess.
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ok i checked my mileage. im doing about 1000 miles per year. I know pathetic. As far as the cost of the Amsoil I dont really care about 75.00 per year. But if there is something better for the 4.0 Tappet engine Im all ears, putting money aside. I get a nasty lifter sticking noise a few times per year. lasts about 10 seconds. So something is going on. But the jeep just rolled 70k so low miles for the year.
 
Originally Posted By: Nick1994
Any old 10w30 would work fine. My 4.0L sits a lot, only 3,000 miles a year or so.

If you're gonna drive it in the freezing cold, use a 5w30.


This.

I have a few UOAs floating around here from my 4.0L Jeep. The quietest running and lowest iron wear numbers I have seen have been from plain ole' Pennzoil conventional 10w30.

I also have some pics floating around from my friend's 2000 Cherokee 4.0 with the valve cover off. It had Pennzoil conventional from new, and the valve-train is spotless.
 
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