Mobil 1 EP - 5W-30 vs 5W-20

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Forget CAFE and all other debates about regular 5W-30 vs 5W-20. This question relates only to the EP formulation. If one is looking to extend the drain to 15,000 miles or more, does the 5W-30 outperform the 5W-20 as it gets further into the interval? Suppose by 13,000 miles, fuel dilution starts to factor heavily, wouldn't that reduce the viscosity of the 5W-20 to a more dangerous, protection level than the 5w-30?
 
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Shouldn't matter. Same formulation, different viscosity. Use what your car calls for. A bit more a safe cushion with the 30 grade if high fuel dilution occurs.
 
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 Originally Posted By: Art_Vandelay
Forget CAFE and all other debates about regular 5W-30 vs 5W-20. This question relates only to the EP formulation. If one is looking to extend the drain to 15,000 miles or more, does the 5W-30 outperform the 5W-20 as it gets further into the interval? Suppose by 13,000 miles, fuel dilution starts to factor heavily, wouldn't that reduce the viscosity of the 5W-20 to a more dangerous, protection level than the 5w-30?
Good question. But it does include a couple unstated assumptions that I think bear critical examination. First, for whatever engine is involved, where exactly does the "threshold of danger" exist? If the threshold of danger is well below the 20 wt vis range, then perhaps a 20 would be just fine. If an engine is designed so that it can't tolerate anything below a 20 wt lube, then yes, the 30 will provide a larger buffer space that the 20 can't. But does anyone really know where these thresholds lie for any given engine?????
 
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I wonder this too. People argue that using a 20w oil is fine because your 30w will eventaually shear down to a thick 20w........ By that logic what says a 20w wont shear down below a 20w grade? My thought is becuase there will be less VII in a 20w to begin with but what if a 20w shear to a 10w... then that WOULD cause worry IMO.
 
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 Originally Posted By: heavyhitter
I wonder this too. . . . By that logic what says a 20w wont shear down below a 20w grade? . . .
Not necessarily. It appears from what we see here that most of the 20wt oils must be more rigorously formulated in order to meet the grade requirements in the first place, and for whatever reason, they don't appear to be shearing down a grade as many of the inexpensive (and some very expensive) 5w-30 oils do routinely. I would simply look closely at the performance of the particular 20 wt in question before passing judgment based upon how a 30 wt oil performs in similar circumstances.
 
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 Originally Posted By: heavyhitter
I wonder this too. People argue that using a 20w oil is fine because your 30w will eventaually shear down to a thick 20w........ By that logic what says a 20w wont shear down below a 20w grade? My thought is becuase there will be less VII in a 20w to begin with but what if a 20w shear to a 10w... then that WOULD cause worry IMO.
I have never seen a UOA, ever, that showed a 20 shearing to a 10. 20 is a pretty broad range of viscosity.
 

Art_Vandelay

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 Originally Posted By: ekpolk
Good question. But it does include a couple unstated assumptions that I think bear critical examination. First, for whatever engine is involved, where exactly does the "threshold of danger" exist? If the threshold of danger is well below the 20 wt vis range, then perhaps a 20 would be just fine. If an engine is designed so that it can't tolerate anything below a 20 wt lube, then yes, the 30 will provide a larger buffer space that the 20 can't. But does anyone really know where these thresholds lie for any given engine?????
I don't have the slightest idea where the threshold of danger lies. My car was originally spec'd for 5W-30, now Ford has back spec'd it to 5W-20. It runs beautiful on 5W-20 and 5W-30. I am working up the nerve to try an extended drain interval, thanks to all the fervor about them on here, and this came to mind. I don't doubt that both additive packages are comparable in terms of longevity. What I'm asking is, with all else being equal, if the underlying 30 weight synthetic fluid can withstand the rigor moreso than a 5W-20. I see 5W-20 as a more advanced product. More difficult to manufacture, therefore requiring more technology to produce. It wouldn't seem absurd that it's lifespan as a lubricant is naturally shorter than 5W-30, merely because it is being asked to do more to begin with. Making it into a long life oil would seem to be a greater task than making 5W-30 long lived. On the other side of it, if 5W-30 does in fact handle fuel dilution better, that alone might be reason for some to choose it over 5W-20. Particularly people for whom city driving makes up a good percentage of the running hours.
 
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If you have a fuel dilution problem, fix it. Otherwise, any normal tiny amount will evaporate and go through the PCV system, and it's not an issue. To go 15,000 miles on oil would make me concerned about additive depletion and contaminant build up. And at those miles, I'd be concerned about oil thickening, not thinning.
 
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Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
 
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Art_Vandelay

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 Originally Posted By: mechtech2
If you have a fuel dilution problem, fix it. Otherwise, any normal tiny amount will evaporate and go through the PCV system, and it's not an issue. To go 15,000 miles on oil would make me concerned about additive depletion and contaminant build up. And at those miles, I'd be concerned about oil thickening, not thinning.
No, I don't have a fuel dilution problem. Just thought that was pretty automatic if you run short trips here and there. I'm concerned to go 7,500 miles on any oil lol, I'm just trying to go with the flow on here. I always did the 3/3000 but hey, change is good. I was simply entertaining the idea of 12 months/ 12,000 miles using EP. In whatever weight was best for my Town Car.
 

Art_Vandelay

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 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Tig1, If it wasn't for you I wouldn't even consider the extended drain ha ha. With the same car, your like my R&D department. If anyone can get the full 15,000 out of the EP you can.
 
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 Originally Posted By: Art_Vandelay
 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Tig1, If it wasn't for you I wouldn't even consider the extended drain ha ha. With the same car, your like my R&D department. If anyone can get the full 15,000 out of the EP you can.
Glad to be of service. Just today a friend brought his 03 Windstar over for an oil change. I work for him and he workes for me. Anyway his Windstar calls for 5-20 but I put M15-30EP in it last year. He forgot to record the miles. When I drained the oil it was that nice amber colar, no grit in the pan, and the inside of the head is clean. 100,000 miles. My guess is he has at least 15,000 miles on the OC, so this time I recorded the date and miles for future reference.
 
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 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Your engine uses different bearing material, and it doesn't show up in most UOA's.
 
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 Originally Posted By: chevrofreak
 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Your engine uses different bearing material, and it doesn't show up in most UOA's.
Just wondering. Are my rod bearings and mains shot and I just don't know it?
 
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 Originally Posted By: tig1
 Originally Posted By: chevrofreak
 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Your engine uses different bearing material, and it doesn't show up in most UOA's.
Just wondering. Are my rod bearings and mains shot and I just don't know it?
It's possible, but I doubt it. The bearing material is some really tough stuff.
 
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 Originally Posted By: chevrofreak
 Originally Posted By: tig1
 Originally Posted By: chevrofreak
 Originally Posted By: tig1
Art, Last Sept. I did my one and only UOA on the Merc. with M1 10-30 at 9700 miles OCI and it came back fine. I now have the 10-30EP in and I may go to 12000 mile OC. I'm a little old fashion but I still go with the 30wt. Notice my sig. as the Focus calls for 20wt. It performs great with the 30wt.
Your engine uses different bearing material, and it doesn't show up in most UOA's.
Just wondering. Are my rod bearings and mains shot and I just don't know it?
It's possible, but I doubt it. The bearing material is some really tough stuff.
You really have my interest going. I used to spray a babbit material for custom bearing when our machine shop would rebuild pumps. Of course this material had lead, tin and other things in it. Do you have any idea what this material is in the 4.6 Ford? Also for the record my 4.6 is as quite as ever, at start up, under hard acceleration, any time. Great engines.
 
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It'll show up in UOA's, you just won't know that's where it's coming from because so many other things are made of aluminum and silicon, and silicon can also come in through the intake.
 
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Simple. 5w-30 because of ACEA A5. A5 is the extended drain spec and no 5w-20 meets it. Everyone else can argue all they want but spec is spec.
 
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 Originally Posted By: chevrofreak
It'll show up in UOA's, you just won't know that's where it's coming from because so many other things are made of aluminum and silicon, and silicon can also come in through the intake.
The UOA I did in Sept 08 only showed 3PPM Aluminum, and 18 PPM Silicon which was well below the avg. for the 4.6. Not bad for nearly 10,000 miles. Thanks for the article on the bearings. Looks like their good stuff.
 
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