Benefit of blending with SAE30?

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13
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NEW YORK CITY
I am running a 2001 jeep 4.0, and was wondering if there is any benefit to adding some straight 30 to another oil. I have read that a straight weight will hold up to shear better than, say a 10w acting as a 30 because is is a real 30 weight. My jeep call for 6 quarts of 10w30, would there be a benefit of mixing 4 quarts 5w30 and 2 quarts sae30 to get a oil similar to 10w30 yet will hold up to shear better? Is this unnecessary with todays synthetics? Thanks
 
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1,067
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Northern, NY
What you are proposing is not necessary. Most conventional 10w30's are pretty shear stable. A lot of the synthetic 10w30's contain little or no viscosity improvers.
 
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3,756
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CA
You could run a straight 30 synthetic like Amsoil ACD that qualifies as a 10w-30 and has better cold flow than many 10w-30s.
 
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682
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ontario canada
10w30 is already highly shear stable. I can't imagine any way a 4.0 could do any significant shearing to it. run 10w30 in the summer and 5w30 in the winter. Ur engine will be really happy. SuperTech is an excellent and reasonably priced synthetic. I u want to spend more, feel free to, but ur engine will not notice any difference. The only reason to possibly consider a straight weight would be if ur engine was in 24 hours a day service, or a taxi cab or something. Multi viscosity oils result in much longer engine life span.
 
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3,756
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CA
 Originally Posted By: scoobie
10w30 is already highly shear stable. I can't imagine any way a 4.0 could do any significant shearing to it. run 10w30 in the summer and 5w30 in the winter. Ur engine will be really happy. SuperTech is an excellent and reasonably priced synthetic. I u want to spend more, feel free to, but ur engine will not notice any difference. The only reason to possibly consider a straight weight would be if ur engine was in 24 hours a day service, or a taxi cab or something. Multi viscosity oils result in much longer engine life span.
Here you go again with your blanket statements. Multi viscosity oils will not always result in a longer engine life span. Name one advantage a 5w-30 has over my straight synthetic 30wt in my climate... There are none. But there are plenty of advantages of the straight weight. The 40cst is 66.3, better than most 10w-30 oils.
 
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682
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ontario canada
USUALLY a multiviscosity is the better choice. There are of course rare exceptions to every rule, but for my engines, with mornings very usually at the freezing mark, I prefer a multiviscosity to get right up there and lubricate ASAP. I just also had the TRIPLE heater installed: heater hose heater, block heater, oil pan heater, and battery warmer. Total: 1480 glorious watts!!! put it on a 3 hour timer, will cost 50 cents a shot, but engine will be instantly warm on start up, to simulate the deep south/mexico etc.
 

KW

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1,686
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Central Arkansas
The 10W30 you are using now should do the trick just fine. HD30 or any mix of it with 10W30 is fine too. My choice for the 4.0 Jeep engine is a 40 weight like 0W40, 5W40, 10W40, 15W40 oils. In New York City I think an oil like Rotella T 5W40 is a good choice.
 
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3,756
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CA
 Originally Posted By: GOOMER
Is Amsoil the only synthetic 30 out there? I can't find any else.
Redline makes a nice straight 30 synthetic and I'm sure there are others, just can't think of them right now.
 
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8,859
Location
Texas
 Originally Posted By: BuickGN
Here you go again with your blanket statements. Multi viscosity oils will not always result in a longer engine life span. Name one advantage a 5w-30 has over my straight synthetic 30wt in my climate... There are none. But there are plenty of advantages of the straight weight. The 40cst is 66.3, better than most 10w-30 oils.
I agree blanket statements are full of holes, but then you really need to point out that the particular straight 30 weight oil you're talking about is NOT a run-of-the-mill 30 but is a special case. It sounds to me like a synthetic 30 that could easily have been certified as a 10w30 had the manufacturer not wanted to profit from the advertizing cachet that straight grades have because VI improvers are not allowed in those grades. The other side of the coin is that VII's are certainly not *necessary* (and certainly not in large quantities) to make 10w30 anymore when we now even non-PAO base oils have VIs in the high 140s. Bottom line, 10w30 vs 30 is *JUST* a rating unless you know more additional info about the oils you're comparing. If instead of a high-end synthetic 30 you take a look at a run-of-the-mill 30wt oil, it will likely have a much lower VI than a comparably run-of-the-mill 10w30 and will not only be thicker when you start the car, but *may* thin out a lot more when you get past 100C oil temperatures too. Is that better? I think not. Now a run-of-the-mill 10w30 from 1975 would indeed have been subject to quite a lot of shearing and long-term degradation at higher temps so it might have been worth it to take the lower VI 30 wt for stability and lack of VIIs. But in 2009, even the average 10w30 is pretty shear-stable and breakdown resistant, and I would venture to say that virtually all current synthetic 10w30s are fairly comparable to your high-quality straight 30. I would venture to go further and say that all the respected brand *0w30* oils are also about as good as your straight 30 because the demands on the base oil VI to meet 0w30 (and 0w20 for that matter) are pretty severe. I am open to some measured evidence to prove me wrong in that regard.
 
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8,859
Location
Texas
 Originally Posted By: KW
In New York City I think an oil like Rotella T 5W40 is a good choice.
' +1 on that. ANYWHERE in north America, RT Synthetic 5w40 is a pretty darn good choice for a Jeep 4.0. I promise I'll post the ~5500 mile RTS 5w40 UOA that I just sent away for my 4.0 when it comes back to get some quantitative info published. Qualitatively, I've been running it since last spring (through an exceptionally hot Texas summer) and right through a winter that saw some low-20s mornings, and the engine seems to just love it. Super stable oil pressure with little variation (about 8 psi at highway speed when comparing stone cold to full operating temp.) Seemingly quieter than with 10w30 also.
 
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3,756
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CA
 Originally Posted By: 440Magnum
 Originally Posted By: BuickGN
Here you go again with your blanket statements. Multi viscosity oils will not always result in a longer engine life span. Name one advantage a 5w-30 has over my straight synthetic 30wt in my climate... There are none. But there are plenty of advantages of the straight weight. The 40cst is 66.3, better than most 10w-30 oils.
I agree blanket statements are full of holes, but then you really need to point out that the particular straight 30 weight oil you're talking about is NOT a run-of-the-mill 30 but is a special case. It sounds to me like a synthetic 30 that could easily have been certified as a 10w30 had the manufacturer not wanted to profit from the advertizing cachet that straight grades have because VI improvers are not allowed in those grades. The other side of the coin is that VII's are certainly not *necessary* (and certainly not in large quantities) to make 10w30 anymore when we now even non-PAO base oils have VIs in the high 140s. Bottom line, 10w30 vs 30 is *JUST* a rating unless you know more additional info about the oils you're comparing. If instead of a high-end synthetic 30 you take a look at a run-of-the-mill 30wt oil, it will likely have a much lower VI than a comparably run-of-the-mill 10w30 and will not only be thicker when you start the car, but *may* thin out a lot more when you get past 100C oil temperatures too. Is that better? I think not. Now a run-of-the-mill 10w30 from 1975 would indeed have been subject to quite a lot of shearing and long-term degradation at higher temps so it might have been worth it to take the lower VI 30 wt for stability and lack of VIIs. But in 2009, even the average 10w30 is pretty shear-stable and breakdown resistant, and I would venture to say that virtually all current synthetic 10w30s are fairly comparable to your high-quality straight 30. I would venture to go further and say that all the respected brand *0w30* oils are also about as good as your straight 30 because the demands on the base oil VI to meet 0w30 (and 0w20 for that matter) are pretty severe. I am open to some measured evidence to prove me wrong in that regard.
You're right in that the 30wt I run is better than your average straight 30wt. I would not recommend a dino 30wt like I do the ACD. I figure if it meets 10w-30 standards with no VIIs, the quality of the base oil is pretty much ensured to be very good. I wouldn't go so far as to say "10w-30 vs 30 is JUST a rating unless you know more additional info". A VII-less 10w-30 is still the exception and not the rule.
 
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8,859
Location
Texas
 Originally Posted By: BuickGN
You're right in that the 30wt I run is better than your average straight 30wt. I would not recommend a dino 30wt like I do the ACD. I figure if it meets 10w-30 standards with no VIIs, the quality of the base oil is pretty much ensured to be very good. I wouldn't go so far as to say "10w-30 vs 30 is JUST a rating unless you know more additional info". A VII-less 10w-30 is still the exception and not the rule.
The only nit I would pick is that I think *most* people would do well to tolerate the small percentage of VIIs that some modern multigrades may have in trade for better cold-start behavior in the 5- and 0w30s. In your application- probably not :-)
 
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8,859
Location
Texas
 Originally Posted By: crazyoildude
if the engine does not burn or leak why not use what the engine calls for??
In many cases I'd agree. But in many, like the Jeep 4.0, oils that didn't exist when the manual was written do a much better job than the ones that did exist. The 4.0 is pretty widely known to like its oil on the heavy side, and you can now get that in many oils that still have a 5w or even 0w cold rating. In other cases, the way the owner uses the engine may be far outside the lowest-common-denominator usage that the manufacturer wrote the recommendation based upon. If it all came down to "just use what the manual says all the time," what the heck are we on here for???
 

GOOMER

Thread starter
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13
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NEW YORK CITY
I am hearing a ton of people say they like the Rotella syn 5w40 in the jeep 4.0. does anyone know what group base Shell is using in it?
 
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