I had to read this 3 times.
Mobil 1 5W-30 -vs- 0W40
- Thread starter ewsmith1
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Patman
Staff member
I know it's hard for a lot of people to think of how a 0w30 oil can be thicker than a 5w30 at operating temp, but when you look at what it takes to qualify as a 30wt, maybe it'll make more sense. In order to be an Xw30 oil, it has to be between 9.3 and 12.49 CST at 100c. A 0w30 oil like Amsoil is pretty thick, it's around 11.9 CST at 100c. But Mobil 1's 10w30 and 5w30s are both at around 9.7 to 9.8 cst at 100c. So you can see how it's possible for there to be vast differences in the oil's viscosity at operating temp, while still actually being within the 30wt range.
I've read quite a few posts here about a lighter winter weight oil (ie 5w30) consuming more than a heavier winter weight (ie 10w30) and I just can't understand it. I do understand it if the 5w30 shears down to a 20wt and the 10w30 doesn't.
I don't think you are going to get any blow-by when the oil has a visc of 50 something. I think the only important visc when dealing with consumption is the visc @ 100C.
Cressida,
For all practical purposes, the Mobil 1, 0w-30/5w-30/10w-30 are the same viscosity @ 210F. However, the 0w-30 and 5w-30 do use lighter basestocks, so they will more readily evaporate at high temps. So even though they are the same viscosity at operating temp, you may see significantly less oil consumption with the 10w-30 than you would with the 0w-30.
The other reason why the 0w-30 evaporates more easily is that some of the VI modifier actually cooks off at high temps. A very wide range synthetic like a 0w-30/0w-40/5w-50 will always have a relatively high evaporation rate, in comparison to a 10w-30/15w-40/20w-50 synthetic.
For all practical purposes, the Mobil 1, 0w-30/5w-30/10w-30 are the same viscosity @ 210F. However, the 0w-30 and 5w-30 do use lighter basestocks, so they will more readily evaporate at high temps. So even though they are the same viscosity at operating temp, you may see significantly less oil consumption with the 10w-30 than you would with the 0w-30.
The other reason why the 0w-30 evaporates more easily is that some of the VI modifier actually cooks off at high temps. A very wide range synthetic like a 0w-30/0w-40/5w-50 will always have a relatively high evaporation rate, in comparison to a 10w-30/15w-40/20w-50 synthetic.
As a general rule, the 5w and 0w oils are more volatile than the 10w. This isn't always the case, but it is the case with M1's 30-weights. I'm running M1 0w-30 now and it didn't shear at all in 7250 miles, however my oil consumption is high with it. My consumption was 3X higher with the M1 0w-30 than it was with the 5w-20 dino oil, and it would have been even higher had I done any amount of freeway driving. I wouldn't recommend the M1 0w-30 for Honda's K20A3 or K20A2 engines for this reason.
Cressida,
cSt @ 40C: 10W-30=61.3, 5W-30=53.7, 0W-30=54.8
cSt @ 100C: 10W-30=9.8, 5W-30=9.7, 0W-30=10.1
Visc Index: 10W-30=145, 5W-30=169, 0W-30=176
Pump Limit: 10W-30=-42F, 5W-30=-51F, 0W-30=-58F
From what I've read on this BB, ALL the M1 stuff tends to run on the low end of whatever range they're in. The greater difference between the 30wt M1s is in the warm-up; the 10W-30's thicker at 40C, & then all the 30s are real close at 100C; I don't know how much difference 0.3, 1, or even 10 cSt makes.
In Eric's case, he's got a brand new engine & a warranty to consider besides his moderate climate. Because he drains so frequently, he probably doesn't need to spend the extra $ on a Grp4 syn, but I understand his desire to use one anyway.
My goals are to decrease my maintenance & volume of waste oil while increasing fuel economy & engine protection. For my non-turbo 1990 Saab, I'd rather run the M1 0W-30 for gas savings & better cold-flow (especially since it's been ACEA upgraded for extended drains, along with the other M1 30wts), but didn't know enough about it when I decided to put in the M1 15W-50; yes, I'm concerned about increased oil consumption because of the age of the engine. In my 1999 turbo, I've decided to switch to the M1 0W-40 for better engine protection at the expense of fuel economy. Right now it loses no oil in 10k mi with a Grp3 10W-30, so we'll see what happens with a 0W.
I'm still trying to sort it all out while not giving myself a mental hernia.
This board's been a fantastic resource for me. I just can't tell if I'm getting less dangerous, or more...
cSt @ 40C: 10W-30=61.3, 5W-30=53.7, 0W-30=54.8
cSt @ 100C: 10W-30=9.8, 5W-30=9.7, 0W-30=10.1
Visc Index: 10W-30=145, 5W-30=169, 0W-30=176
Pump Limit: 10W-30=-42F, 5W-30=-51F, 0W-30=-58F
From what I've read on this BB, ALL the M1 stuff tends to run on the low end of whatever range they're in. The greater difference between the 30wt M1s is in the warm-up; the 10W-30's thicker at 40C, & then all the 30s are real close at 100C; I don't know how much difference 0.3, 1, or even 10 cSt makes.
In Eric's case, he's got a brand new engine & a warranty to consider besides his moderate climate. Because he drains so frequently, he probably doesn't need to spend the extra $ on a Grp4 syn, but I understand his desire to use one anyway.
My goals are to decrease my maintenance & volume of waste oil while increasing fuel economy & engine protection. For my non-turbo 1990 Saab, I'd rather run the M1 0W-30 for gas savings & better cold-flow (especially since it's been ACEA upgraded for extended drains, along with the other M1 30wts), but didn't know enough about it when I decided to put in the M1 15W-50; yes, I'm concerned about increased oil consumption because of the age of the engine. In my 1999 turbo, I've decided to switch to the M1 0W-40 for better engine protection at the expense of fuel economy. Right now it loses no oil in 10k mi with a Grp3 10W-30, so we'll see what happens with a 0W.
I'm still trying to sort it all out while not giving myself a mental hernia.
In the Supersyn family
0/40 21,700 cold pumping cp @ 40C
0/30 22,600 " "
5/30 23,900 " "
10/30 10,250 " "
15/50 14,050 " "
Does that mean the 10/30 and the 15/50 has less adds to burn off and more syntetic base oil in a quart? Are these two the most stable of the rest?
Is the 10/30 also the superior cold weather oil?
0/40 21,700 cold pumping cp @ 40C
0/30 22,600 " "
5/30 23,900 " "
10/30 10,250 " "
15/50 14,050 " "
Does that mean the 10/30 and the 15/50 has less adds to burn off and more syntetic base oil in a quart? Are these two the most stable of the rest?
Is the 10/30 also the superior cold weather oil?
Those numbers are:
Cold Cranking first and cold pumping second, CP @ °Celsius
0/40 4,301@-35° 21,700@-40°
0/30 3,800@-35° 16,250@-40°
5/30 3,600@-30° 12,700@-35°
10/30 3,848@-25° 10,250@-30°
15/50 5,234@-20° 14,050@-25°
Cold Cranking first and cold pumping second, CP @ °Celsius
0/40 4,301@-35° 21,700@-40°
0/30 3,800@-35° 16,250@-40°
5/30 3,600@-30° 12,700@-35°
10/30 3,848@-25° 10,250@-30°
15/50 5,234@-20° 14,050@-25°
Eric,
The revised M1 specs dated 10/02 are listed as:
cSt @ 40C: 5W-30=53.7, 0W-30=54.8
cSt @ 100C: 5W-30=9.7, 0W-30=10.1
Visc Index: 5W-30=169, 0W-30=176
Pump Limit: 5W-30=51F, 0W-30=58F
(These numbers are the same as the specs dated 8/02; they corrected some other misprints.)
So, yes, there is a slight all-around benefit to the 0W-30. I'm still just guessing that the 0W-30 won't leak any more than the 5W-30 since it's already thicker at 40C/104F than the 5W-30, but that it probably will blow-by more at cold start (when it IS thinner) in a worn engine. I'm also guessing that evaporation may be slightly higher, but not to the point where it would catch up to what the 5W-30 would be doing in the same period of time.
The revised M1 specs dated 10/02 are listed as:
cSt @ 40C: 5W-30=53.7, 0W-30=54.8
cSt @ 100C: 5W-30=9.7, 0W-30=10.1
Visc Index: 5W-30=169, 0W-30=176
Pump Limit: 5W-30=51F, 0W-30=58F
(These numbers are the same as the specs dated 8/02; they corrected some other misprints.)
So, yes, there is a slight all-around benefit to the 0W-30. I'm still just guessing that the 0W-30 won't leak any more than the 5W-30 since it's already thicker at 40C/104F than the 5W-30, but that it probably will blow-by more at cold start (when it IS thinner) in a worn engine. I'm also guessing that evaporation may be slightly higher, but not to the point where it would catch up to what the 5W-30 would be doing in the same period of time.
No. You can't directly compare the cold pumping and cold cranking specs across the cold temp designations like that. You can directly compare a 0w's cold cranking and cold pumping specs with another 0w but not a 5w. For a synthetic oil, it's viscosity will increase by about 1.7 every -5*C change in temp. So if you want to guesstimate what M1's CP spec would be at -35*C, it would be 10,250cP X 1.7 = 17,425cP.
Where does that come from? In the above specs, a -5C drop results in 3-5 times the thickness.
Dr T,
Actually the M1, supersyn is ACEA A5/B5 rated in the 0w-30/5w-30/10w-30 grades. If you go to the Lubrizol website you'll see that the A5/B5 oils have to pass the same tests as the ACEA A3/B3 oils. They are basically low viscosity versions of the older, thicker formulations.
Most newer VW/Audi engines in Europe call for the VW 503/506 spec oils, which are primarily 0w-30 grades. These roughly correspond to A5/B5 oils ....
Actually the M1, supersyn is ACEA A5/B5 rated in the 0w-30/5w-30/10w-30 grades. If you go to the Lubrizol website you'll see that the A5/B5 oils have to pass the same tests as the ACEA A3/B3 oils. They are basically low viscosity versions of the older, thicker formulations.
Most newer VW/Audi engines in Europe call for the VW 503/506 spec oils, which are primarily 0w-30 grades. These roughly correspond to A5/B5 oils ....
I think I got it from TooSlick who has posted this many times. I've checked the figure on a temp/vis chart and the conversion is reasonably accurate at low temps.
Ross,
It seems that the main reason that 40 wt. oils are not recommended is to give the auto makers a sliver better fuel mileage to avoid CAFE penalty payments.
The big spread in vis numbers, 10W-40, etc., relates to conventional oils...they need to add too much viscosity index improver (VII) additive. Synthetic oils listed as 0W-40, 5W-40, 15W-50, etc., have an inherently higher viscosity index due to the superior base stocks, and need less VII.
A 0W oil is only thinner than a 5W or 10W oil at low temperatures. A 0W-30 and 10W-30 are essentially the same viscosity at operating temps.
Mobil1 0W-40 is a different formulation than the xW-30s. Mainly, it has superior High Temp/High Shear viscosity specs. Yes, it's a slightly better oil.
Your M1 TS 5W-30 is still an excellent oil. Use it up and feel good about it. We've also heard that the new Mobil 1 0W-30, 5w-30, and 10W-30 are essentially the same oil with different labels for marketing purposes.
Ken
They are not the same oil.
VaderSS, Pops, I found a good example of what I talked about earlier about comparing cold cranking and cold pumping specs. Here are some CC and CP specs from Schaeffer's #700 Supreme 7000 15w-40:
CCS Viscosity @ -15°C cP (ASTM D-5293)
1,775
CCS Viscosity @ -20°C cP (ASTM D-5293)
2,804
CCS Viscosity @ -25°C cP (ASTM D-5293)
4,877
Mini-rotary Viscosity-TP.1 @-25°C cP (ASTM D-4684)
14,368
The cold cranking specs are shown at 3 different temperatures which is rare. Usually only the CC for the 15W rating is shown and that's at -20 *C. You can see that the dynamic viscosity increased about 1.6 times from -15*C to -20*C and 1.7 times from -20*C to -25*C. That's where the 1.7 comes from. The cold pumping spec will change similarly every 5*C.
Another interesting thing: This oil could qualify as a 10w-40 oil if Schaeffers chose to market it that way. It already passes the ASTM D-5293 test for the 10w designation and we can estimate that the CP viscosity will be 1.7 X 14,368 cP ~ 24,500 @ -30*c. So it will easily pass the ASTM D-4684 test for 10w also.
CCS Viscosity @ -15°C cP (ASTM D-5293)
1,775
CCS Viscosity @ -20°C cP (ASTM D-5293)
2,804
CCS Viscosity @ -25°C cP (ASTM D-5293)
4,877
Mini-rotary Viscosity-TP.1 @-25°C cP (ASTM D-4684)
14,368
The cold cranking specs are shown at 3 different temperatures which is rare. Usually only the CC for the 15W rating is shown and that's at -20 *C. You can see that the dynamic viscosity increased about 1.6 times from -15*C to -20*C and 1.7 times from -20*C to -25*C. That's where the 1.7 comes from. The cold pumping spec will change similarly every 5*C.
Another interesting thing: This oil could qualify as a 10w-40 oil if Schaeffers chose to market it that way. It already passes the ASTM D-5293 test for the 10w designation and we can estimate that the CP viscosity will be 1.7 X 14,368 cP ~ 24,500 @ -30*c. So it will easily pass the ASTM D-4684 test for 10w also.
MolaKule
Staff member
Good point, say a 10W15W40
The main difference between ACEA A3-02 and A5-02 is that the A3 has a tougher High Temp/High Shear spec...>3.5 for the A3 and 2.9 to 3.5 for A5
http://www.acea.be/ACEA/20020618PublicationsOilSequences.pdf
Ken
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