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ok so here lately I have been having difficulty finding ACEA A3 labeled mobil 1 10w30HM. BUT I have been able to find planty of ACEA A3 mobil 1 10w40HM. is the difference between 10w30 & 10w40 worth worrying about or should I keep searching for 10w30.

my jeep has 72k miles and my gf's has 85k miles just for reference purposes
 

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Not sure what any of the hard-core oil folks will tell you but 10w40 used to be the standard of what we ran in ALL our rigs for years. The Jeep is the first I've had that called for 10w30, followed by our Subaru which wants 5w30. Jeep is an '05, Sub is '07. With the ZDDP level issues for our engines, I talked with the guys at Royal Purple and they said NOT to add anything to the oil, but instead recommended I switch to 10w40 as it by allowed government specs to have higher ZDDP levels due to weight. They said to switch to 10w40 and not worry about a thing. I did, and have had no issues to date on the current fill, but again, it's been recent and I doubt I have 3000 miles on it yet. I've noticed no difference in running-other than it is a titch quieter, no difference in oil pressure on our dummy guage, no other engine related issues at all. Again, too soon for long term results...

Best of Luck,

Mike
 

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10w40 would be a bit thicker and may make it harder to start in cold weather. I know I find 10w30 HM at walmart. It is usually cheaper to wait until Napa/autozone/oreily's has the 5 qts and filter for 29.99 sale.
 

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The difference is that the 10w40 has more multigrade additives than the 10w30. So when you are burning a tiny bit of oil (say a half quart between changes) there will be more "carbon" deposits from the 10w40. Those additives are basicly a refined type of clay, so they are left behind when the hydrocarbons burn off. It's a witches brew of chemicals in a "carbon" deposit, but primarily carbonites and calcites from the clay additives, plus ash from impurities in gasoline.
 

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Elwarpo said:
10w40 would be a bit thicker and may make it harder to start in cold weather. I know I find 10w30 HM at walmart. It is usually cheaper to wait until Napa/autozone/oreily's has the 5 qts and filter for 29.99 sale.
until now I have only been able to find 10w30HM at walmart around here, but like I said its become more difficult to find here lately. 5qt bottles are non existant and the few single qt bottles I found did not have the ACEA A3 labeling.

so kaiserjeep, are you saying I SHOULD NOT run the 10w40 because of the additives, or should I just make sure I run seafoam a lil more often to clean out those deposits ?

thanks in advance
 

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Hey guys, 10w-40 and 10w-30 will have the same additive package, it's the viscosity or "thickness" that will be different. I wouldn't switch to a thicker oil going into winter. I run a 0w-30 year round, mainly because I get it for free, but look for a 5w-30 or 0w-30 going into winter. I assume it gets cold in Maryland? You'll be in good shape if you run a lower "w" rated oil in the cold, it does'nt hurt to run it in the summer either. The main lesson here is the "w" stands for Winter and not Weight. The lower the number, the better it will flow in the cold. Surely you can find some 5w or 0w oil in your area, with winter coming I would think it would be easier to find, good luck.

Todd
 

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its not the fact that I cant find 5 or 0 oil, its finding the oil that has the right ACEA rating on it. if you are just using whatever oil you can get for free and you have a 4.0L, I have a feeling you will be experiencing came lobe or lifter failure in the next couple years. thaks to major changes in the oils over the last few years the ole reliable Jeep I6 aint so bulletproof any longer
 

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I think this got missed so I am posting again.
so kaiserjeep, are you saying I SHOULD NOT run the 10w40 because of the additives, or should I just make sure I run seafoam a lil more often to clean out those deposits ?

thanks in advance
 

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ive been building engines and abusing them for years in all climates/conditions. ive ran whatever was on the shelf in oil and filters and never had an issues whatsoever. i think we are all getting way too involved in this oil and filter debate. just my opinion but " pour it in and go!"
 

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wickedrubi said:
ive ran whatever was on the shelf in oil and filters and never had an issues whatsoever. i think we are all getting way too involved in this oil and filter debate. just my opinion but " pour it in and go!"
Been thinking the same for years now... Wonder how many would choke if I told them I used to run 20w50 in a few rigs during the summer. :laugh:

The Jeep and the Subaru are the first I've run with light weight 5w30 and 10w30. Jeep now has 10w40-yes, even through the winter months :eek: . Just swapped it in not too long ago actually and likely won't go back to the lighter stuff again.

Best of Luck,

Mike
 

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Right now I am running 15w40 in both jeeps, the sport starts just fine with it and the rubi cranks a tad slower. That being said, my old chevy truck at 225,000 miles has always had 20w50 at every 5,000 miles until recently, cold weather running I would be easy on it for a few miles. The next time around I'll put 10w40 in both Jeeps, the 10w should help for cold startup and the 40 side will help with operating temp use. Right now the butt meter says that with the 15w40 both jeeps run smoother. Just my 2cents.
 
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Hey guys and girls, I spent a lot of time trying to find the best oil we can run in our flat tappet 4.0 engines. I went into the Corvette forum and several others and also several jeep sites. A lot are recommending the VR-1 Valvoline racing oil as it states not for street use, because it has the right Zinc amount in the oil it can't be sold for street use. that's how Valvoline gets around the Zinc additive they add to it. I have always changed my oil at 3,000 or more often when rubi sits during the winter. I always felt with 3,000 or shorter oil changes the regular good quality 10-30 oils would probably be ok. With the amount of cam problems increasing on all flat tappet engines with the low zinc content present in the oils these days I've changed my mind on this. Some are running Shell Rotella which is a diesel oil to get a good zinc level in the oil. This was made for diesel motors by Shell and has a good zinc content. You can always buy a zinc additive for the oil you use, but why pay the xtra $. and the hassel to order and stock. I'm going to change over to Valvoline VR-1 10-30 and see what happens. Some say the Zinc may cause premature converter problems, who knows? I'd rather have to replace my cat then my cam and lifters or possibly the motor due to metal contamination. Looking to make the old flat tappet out last me.
Ron
 

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MPETE said:
I think this got missed so I am posting again.
so kaiserjeep, are you saying I SHOULD NOT run the 10w40 because of the additives, or should I just make sure I run seafoam a lil more often to clean out those deposits ?

thanks in advance
I actually think that you can run any grade of oil authorized in the TJ Owner's Manual, which is any multigrade oil with A specified SAE viscosity rating and an API Quality Classification. MOPAR specifies that 5w-30 is "preferred" for 32 degrees F and below, and 10w-30 is "preferred" for 0 degrees F and above. "Preferred" in this case means that these are the grades that maximize fuel economy.

10w-40 is a non-preferred grade that will cost you a bit of fuel economy because it will be thicker than 10w-30 when the engine is hot. It will also make more carbon when your engine is mildly ill and burning a bit of oil, because of the higher amount of multi-viscosity clay additives.

I pretty much follow the MOPAR reccomendations for the first 100,000 miles. In California's mild climate, I run 10w-30 all year. Where I depart from the MOPAR reccomendation is when the engine goes above 100,000 miles. Then I switch to 20w-50 because I think it restores some lost oil pressure and clings to worn bearing surfaces better. Just something my old man taught me - he started running the AMC I-6 engines in the 1960's in Rambler automobiles.

As for Sea Foam, I DO NOT run it or any other additive intended to loosen or remove carbon. Firstly because I believe that any such additive is totally useless for the stated purpose. Secondly, if the additive were to ever start to work as described, then both the pre-cats in the manifold and the rear catalytic converter would be destroyed by the loose carbon. I believe the only way to remove carbon is to remove the cylinder head and use scrapers and abrasives. I also believe that such is only necessary when carbon has built up to the point where pinging happens and the engine diesels after shutoff.

The dieselling only happens on carbureted engines, so that symptom is only found on older Jeeps. But if your engine pings and you can't stop it by buying the next higher grade of fuel, time to disassemble the head and remove the carbon, in a safe procedure that will not destroy the converters.
 

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Discussion Starter #14
ok
thanks for the advice.
 
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