Another "what oil" for my Jeep 4.0 thread

[Brandon04GT]

Hello everyone. First post here. I try my best not to make these types of threads but I can't seem to find anything definitive yet.

I recently bought a used Jeep with a 4.0 and
In my past cars, I have used Mobil 1 with a Mobil 1 filter without issue and have been happy with it. Initially, I had planned to do the same with this car but read that these engines are old technology and really like oils high in zinc/ZDDP (?????). As I understand it, modern regulations demand most oils to have very little ZDDP.

I've read of people using Shell Rotella for it's high ZDDP content but have also read that the oil is designed for heavy-duty cars without catalytic converters as the ZDDP is bad for the cats.

Further, I've also read of people using Mobil 1 high-mileage for it's higher ZDDP content than the regular Mobil 1 line. I was under the impression that high-mileage oil usually contains seal swellers and etc. with can wear down otherwise good internals. I don't know if high-mileage oil should be reserved only for really old cars on their last leg of life?

Anyway, I was just wondering if any of you oil gurus can make a recommendation on what to use. I'd like to stick to one brand to use from here on out.

Also, if there are any Jeep peeps here, is the factory 10w30 spec along with the stated 6 quarts both optimal? Only asking because in one of my previous cars it had been known that a slightly thicker oil along with more quantity was actually more beneficial than factory spec.


Thanks!!!

 

[montero1]

Did you just call your Jeep a "car"? Grrrrr.

 

[KCJeep]

This has been beat to death here but you are on the right track. Here's some good reading for you.

Jeep 4.0 on Bob

Bob again

Again

Again

Another

Yet again

There are a lot more than that but that will get you started. I'm not being a smarty I know the search on here is difficult to use at best.

Welcome to BITOG!

P.S. DO NOT refer to a Jeep as a "car".

 

[KCJeep]

My condensed thoughts:

Fear not a high mileage oil, internet myth.

Yes thicker for grade is better in the 4.0, a thick 30 or thin 40 is just the ticket IMO.

After countless hours reading UOA's I'd suggest PYB, Valvoline (any), Defy or Rotella. They PYB will be the quietest running followed by the Defy.

 

[901Memphis]

Mobil 1 High Mileage 10W30

Pennzoil yellow bottle 10w30

Rotella T5 10w30

Those are my top three picks.

 

[KzMitch]

And as a former CJ-7 owner, please don't refer to them as cars.
It's disparaging to cars.

 

[toneydoc]

I have the same engine in a 94 that I bought new. It has had many different oils and did not care one way or the other. I change it out around 4k miles now. It is running Valvoline Next gen at the moment. No problems and it is a 5w30 grade.
I have had zero problems with the motor. Few things like leaky radiator, some corrosion with distributor and wires, changing plugs periodically, and she just keeps going. Drove it today.
Enjoy that engine. Gas mileage not great but good pulling engine

 

[dlundblad]

All the above oils mentioned are great for the 4.0.

Too many people seem to get caught up in the zinc thing.. I used to be as well, but I have seen time and time again that it isn't necessary. Its not a high compression V8 out of a muscle car. They do seem to like oils that have it though, but my own opinion is that its because they like thicker oils.. thick heavy duty oils normally contain a bit more zinc.

If a high zinc HM oil is what you prefer, I would have to say Defy. Pennzoil conventional (PYB) and their HM oil have a lot (well above average) of an additive called molybdenum (moly) that 4.0s really seem to love.. more so than zinc I would have to say.

 

[Brandon04GT]

Thanks everyone for the responses. I looked at the links and I am seeing Rotella come up a lot, but can't find anything to address the issue of it being bad for catalytic converters? We have pretty stringent emission regulations here in CA.

Most of you are also recommending the Pennzoil yellow bottle. I do see that it is dino oil and has the lowest rating on the Pennzoil site for cleansing/protection. Not sure if that could mean I could do better?

I've always been under the impression that synthetic would be in the best interest of an engine if you want it to last long and you can get it started on synthetic before it's way too late? But I'm getting the vibe I may not be thinking correctly as to all this.

 

[dlundblad]

Its just their entry level oil.

Conventional
HM
Blend
Platinum
Ultra

They have an HM synthetic now.. not sure where that falls in comparison to the rest tough.

 

[KCJeep]

Originally Posted By: Brandon04GT
Thanks everyone for the responses. I looked at the links and I am seeing Rotella come up a lot, but can't find anything to address the issue of it being bad for catalytic converters? We have pretty stringent emission regulations here in CA.

Most of you are also recommending the Pennzoil yellow bottle. I do see that it is dino oil and has the lowest rating on the Pennzoil site for cleansing/protection. Not sure if that could mean I could do better?

I've always been under the impression that synthetic would be in the best interest of an engine if you want it to last long and you can get it started on synthetic before it's way too late? But I'm getting the vibe I may not be thinking correctly as to all this.


Rotella won't cause any converter problems unless your 4.0 uses oil (most don't) and even then it would be a very long term thing.

PYB is one of the very best, if not the best conventionals available. Don't let Pennzoils site fool you that is about marketing. In fact, if you can find a conventional with more detergents in it than PYB I'd like to know about it. PYB is crazy good and the Jeep 4.0 seems to love the stuff many 4.0 owners have noted that.

There is nothing wrong with synthetics but I honestly think the 4.0 does better on plain old conventionals.

 

[DoubleWasp]

Regardless of what the ingredients are, or its place in the hierarchy, PYB is turning in ridiculously good numbers on UOA'S with our engines.

 

[crazyoildude]

Use 10w30 pennzoil yellow bottle in the winter and 10w30 Pennzoil high mileage in the summer.. Those 4.0 engines run well for a long long time as long as you don't overheat them

 

[Brandon04GT]

Originally Posted By: KCJeep
Originally Posted By: Brandon04GT
Thanks everyone for the responses. I looked at the links and I am seeing Rotella come up a lot, but can't find anything to address the issue of it being bad for catalytic converters? We have pretty stringent emission regulations here in CA.

Most of you are also recommending the Pennzoil yellow bottle. I do see that it is dino oil and has the lowest rating on the Pennzoil site for cleansing/protection. Not sure if that could mean I could do better?

I've always been under the impression that synthetic would be in the best interest of an engine if you want it to last long and you can get it started on synthetic before it's way too late? But I'm getting the vibe I may not be thinking correctly as to all this.


Rotella won't cause any converter problems unless your 4.0 uses oil (most don't) and even then it would be a very long term thing.

PYB is one of the very best, if not the best conventionals available. Don't let Pennzoils site fool you that is about marketing. In fact, if you can find a conventional with more detergents in it than PYB I'd like to know about it. PYB is crazy good and the Jeep 4.0 seems to love the stuff many 4.0 owners have noted that.

There is nothing wrong with synthetics but I honestly think the 4.0 does better on plain old conventionals.



Sounds good, thank you. I guess Pennzoil YB 10w30 it is. I presume the 4.0 is not known to run better on a particular type of oil filter? If so, I suppose I'll stick to a Mobil 1 filter unless there is something truely just as good for cheaper.

Just one last thing....Since PYB is dino oil, will this mean strict 3k mile oil changes from now on?

Also, so just to better understand this whole dino vs. synthetic thing, when you hear about these 4.0 Jeeps going 250 and even 300k miles....these engines could really last that long with dino oil?

And moly....I do seem to frequently run across that word. IIRC, it's that graphite super anti-friction additive right?

 

[901Memphis]

4.0s like Fram Tough Guards. High efficiency media with a silicone anti drain back valve. Actually the Mobil 1 filter is somewhat similar with a high efficiency synthetic blend media and silicone valve to but the TG is usually cheaper at Walmart $6 vs $10+ for the M1 at a parts store.

If you want to spend Mobil 1 money get the Fram Ultra which is good for 15,000 miles even if you want to change the oil and keep the filter on, that's what I do. Oil change every 5k, filter every 15k. Fram Ultras are approximately $9 at Walmart depending on model. Can find deals on the Web for many brands. Recently I got Fram Ultras off Amazon for less than $6 each.

 

[Nickdfresh]

Originally Posted By: KzMitch
And as a former CJ-7 owner, please don't refer to them as cars.
It's disparaging to cars.


LOL

 

[Nickdfresh]

Originally Posted By: Brandon04GT
....these engines could really last that long with dino oil?

...


Of course! With frequent oil changes absolutely...

 

[KCJeep]

The PYB is my pick as well, after trying and researching a host of others. It's a crazy good conventional with a high TBN, so high it rivals some HDEO's. Amazing. Anyway it should be good for more than 3k unless you short trip yours to death. Normal use probably more like 5k.

Filters do make a difference on some 4.0's, mine is notoriously picky and I think I've spent more time testing filters than oil LOL. As mentioned the Fram Tough Guard does very well on these engines, as do any of the Napa Silvers that fit (not Gold, trust me) and the Motorcraft FL-400s. Currently running a Silver #31516 which is about as good as it gets for my Jeep.

My previous 4.0 could care less about the filter and I could run anything, maybe yours is that way as well.

Pennzoil is crazy high in moly already. No need for the additive unless you want to. I want to, but for other reasons.

 

[Brandon04GT]

Sounds good! Actually, I was just out and after reading so many good reviews about WIX filters and noticing that they're about half the price of an Mobil 1, I decided to swing by the nearest store that carried them and bought the one left they had in stock.

I then went to Walmart to look for PYB and pick up some other unrelated stuff. They only had one 5-quart jug of 10w30 left so I grabbed that. I was hoping to pick up a couple of them to reach the 6 quarts I need but ended up having to get ripped off by buying a small 1-quart bottle....which they only had one left of also.

I guess tonight was my lucky night lol. So, I hope I made a good choice with the oil/filter combo?

 

[bubbatime]

Your vehicle has an fairly high miles and an unknown maintenance history. I would not use a synthetic oil in that application and would run Quaker State Defy 10W30/10W40, your pick.

Edit: The Pennzoil you bought is a good oil. Will serve you well. You will probably need top off oil, so should have bought the two 5 quart jugs instead.