Mobil 1 0W-40 or GC 0W-30 for Northeast Winters?

[pipo]

Are you saying that the MRV and CCS are of academic interest only because ambient temperatures in MA are never as low as -35 and -40C, and these measurements are not useful for purposes of extrapolating to higher sub-freezing temperatures? If that's the case, these measurements are pretty much useless except in the Arctic.

If I understand you correctly, though, the HTHS viscosity is a more useful comparative measure than KV, at least down to about -10C (approx. 14F), for purposes of predicting start-up viscosity. So the next question is, if we would like to compare cold starting viscosities and we have the HTHS viscosity and the viscosity index of two oils, how do we do it? Is there an online calculator? Without a calculator, isn't it right that only two oils with either identical HTHS viscosities or identical VIs could be compared at -10C on the basis of the non-identical test result?

Finally, you say that we know that it's not correct that M1 0W-40 is lighter than M1 0W-30 at temps below -10C. How do we know that if the MRV spec is only relevant at the actual temperature at which it is determined and has no predictive value for other temps? M1 0W-40 has a higher HTHS viscosity and a higher VI than the M1 0W-30, so without a calculator how can we comparatively predict even the -10C cold starting viscosity? And even if we could, how can we say anything about the viscosities between -40 and -10C?

Just trying to wrap my brain around this, and it seems that the oil companies aren't providing the specs that would have real-world value for predicting cold starting viscosity... At least not easily.

 

[SubLGT]

Originally Posted By: A_Harman
...............I wish somebody would make a study of oil viscosity in the range of -15 to 25C. This is the temperature range where most people start their engines up after soaking down to ambient temperature. API testing is targeted toward the extremes.


Maybe the answer is in: Oil Flow Studies at Low Temperatures in Modern Engines

http://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1388.htm

 

[dparm]

It's not the oil companies holding back the specs, it's that the SAE tests only measure at the two extremes.

 

[pipo]

Originally Posted By: SubLGT
Originally Posted By: A_Harman
...............I wish somebody would make a study of oil viscosity in the range of -15 to 25C. This is the temperature range where most people start their engines up after soaking down to ambient temperature. API testing is targeted toward the extremes.


Maybe the answer is in: Oil Flow Studies at Low Temperatures in Modern Engines

http://www.astm.org/DIGITAL_LIBRARY/STP/SOURCE_PAGES/STP1388.htm


From what I found in looking at the editor's overview in these materials (dating back to 2000), the holy grail had not yet been discovered, but there was a lot of research in progress. A couple of interesting points:

• Modern engines crank at much lower temps than before, so care has to be taken to ensure pumpability at these lower temperatures
• the ccs and mrv viscosity specs are intended to protect against this risk
• used oil may be at greater risk of reduced pumpability at low temperatures
  
  Is this perhaps a prescription for fresh oil just before the start of the coldest months in cold weather climates?

 

[dparm]

Perhaps. It has been proven that topping-off oil can greatly improve its life by replenishing depleted additives. Some have even used those moly additive bottles to help bolster old oil.

I'm not sure if additives alone are enough to improve cold weather pumpability and flow, however, or if it comes down to the base oil itself (I suspect it's the later).

 

[CATERHAM]

Originally Posted By: pipo
Are you saying that the MRV and CCS are of academic interest only because ambient temperatures in MA are never as low as -35 and -40C, and these measurements are not useful for purposes of extrapolating to higher sub-freezing temperatures? If that's the case, these measurements are pretty much useless except in the Arctic.

Yes that's exactly what i'm saying.
As an aside, an oil with a low MRV value is an indicator of the use of higher quality base oils. 0W-XX oils tend to use higher quality base stocks than 5W-XX oils.

Originally Posted By: pipo

If I understand you correctly, though, the HTHS viscosity is a more useful comparative measure than KV, at least down to about -10C (approx. 14F), for purposes of predicting start-up viscosity.

HTHS vis' takes temporary shear and pressure into consideration so it is a more accurate measure of viscosity as it applies to an IC engine.
So oils with the same HTHS vis and the same VI's will have the same virgin viscosities at all temp's down to about -10C.
If one oil has a higher VI then it will become progressively lighter as the temp's drop; most significantly so when you get down around the freezing point.

 

[CATERHAM]

Originally Posted By: pipo
So the next question is, if we would like to compare cold starting viscosities and we have the HTHS viscosity and the viscosity index of two oils, how do we do it? Is there an online calculator? Without a calculator, isn't it right that only two oils with either identical HTHS viscosities or identical VIs could be compared at -10C on the basis of the non-identical test result?

There is no online calculator, I wish there was.
Or what would be better is viscosity spec' at say 0C using the HTHS or MRV methodology. But there isn't so we work with what we're given.
Originally Posted By: pipo

Finally, you say that we know that it's not correct that M1 0W-40 is lighter than M1 0W-30 at temps below -10C. How do we know that if the MRV spec is only relevant at the actual temperature at which it is determined and has no predictive value for other temps? M1 0W-40 has a higher HTHS viscosity and a higher VI than the M1 0W-30, so without a calculator how can we comparatively predict even the -10C cold starting viscosity? And even if we could, how can we say anything about the viscosities between -40 and -10C?

I would say MRV is relevant for all extreme temp's and in the case of 0W-XX oils from -40 degrees up to -20C or so. Yes there is some uncertainty in that -20C to -10C area (you could even broaden the range from -25C to -5C).
But I don't really see a problem here.
If you live in a climate like a friend of mine in Edmonton Alberta where the winter temp's routinely drop down to -30C and even -40 on occation then yes MVR is important no question if you ever have to start a vehicle unaided.
But in a milder climate where the winter temp's tend to hover around the freezing point and even dropping on occation into the -20C's as they do in my area, MVR plays no role. I rely on HTHS and VI solely to compare start-up viscosities of different oils.

 

[OhioSienna]

FWIW, I've run both M1 0W-40 and GC 0W-30 in my Passat B5.5 1.8T in the winter, and the fuel economy is substantially better with M1. Since M1 meets the manufacturer's specs, that's what I'm sticking with.

 

[Quattro Pete]

Originally Posted By: OhioSienna
FWIW, I've run both M1 0W-40 and GC 0W-30 in my Passat B5.5 1.8T in the winter, and the fuel economy is substantially better with M1.

Interesting. I ran these two oils in my A4 1.8T and haven't seen any noticeable MPG difference. GC may have also made the engine a bit more quiet, but that may have just been all in my head.

 

[pipo]

Originally Posted By: OhioSienna
FWIW, I've run both M1 0W-40 and GC 0W-30 in my Passat B5.5 1.8T in the winter, and the fuel economy is substantially better with M1. Since M1 meets the manufacturer's specs, that's what I'm sticking with.


That's probably what we would predict based on the M1's substantially higher viscosity index. I would hypothesize that at operating temps, the GC would do a little better due to its slightly lower HTHS viscosity, but that the M1 would do significantly better at cold weather starting temps and until the oil warms up. The M1's cold weather mpg advantage would be greater if you do a lot of short trips rather than mostly highway miles, I would think.

 

[OhioSienna]

Interesting. I am a short-tripper, with a home-to-work distance of about a mile.

 

[dparm]

The M1 with higher viscosity index is probably a better fit. It's just a more modern formulation anyways. GC is getting to be "old".

 

[pipo]

Originally Posted By: dparm
The M1 with higher viscosity index is probably a better fit. It's just a more modern formulation anyways. GC is getting to be "old".


This has been a very educational exercise for me, and I appreciate all of the responses. It's clear that some of you - you know who you are! - are "oil professors."

Goes to show, however, that even in this brave new world of rapidly advancing technology, the information that would be most useful to us as consumers isn't always available: in this case, real world low temperature viscosities.

dparm, would you mind expanding a bit on your last post, to explain in what respect the GC formulation is getting "old," and perhaps to identify other oils with more modern formulations? For example, a couple of posters recommended M1 0W-30. Modern formulation?

 

[Quattro Pete]

M1 AFE 0w-30 may be a more modern formulation, but it was designed with a different purpose/target in mind: mainly improvement of fuel economy. If you need an oil meeting VW 502.00 spec (HT/HS of at least 3.5 cP), then M1 0w-30 isn't your oil.

As far as GC getting old comment, from what we know, GC's formulation hasn't changed since about 2004 or so. However, that does not necessarily make it bad. It is certainly still good enough to meet all the stringent German mfg specs. Also, we don't know for sure that GC's formulation hasn't changed. Not everything will show up on a $20 VOA... But most likely it's still the same.

 

[pipo]

Originally Posted By: Quattro Pete
M1 AFE 0w-30 may be a more modern formulation, but it was designed with a different purpose/target in mind: mainly improvement of fuel economy. If you need an oil meeting VW 502.00 spec (HT/HS of at least 3.5 cP), then M1 0w-30 isn't your oil.

As far as GC getting old comment, from what we know, GC's formulation hasn't changed since about 2004 or so. However, that does not necessarily make it bad. It is certainly still good enough to meet all the stringent German mfg specs. Also, we don't know for sure that GC's formulation hasn't changed. Not everything will show up on a $20 VOA... But most likely it's still the same.




I was thinking maybe 4 quarts of M1 0w-40 and 2 quarts of M1 0W-30, to keep the HTHS viscosity at about 3.5. Anything else about the M1 0W-30 that varies significantly from the 502 spec that I should be concerned about? I noticed that the TBN and SAP are a bit lower, so the oil might deplete faster, but I believe some of the other 502 oils have lower TBN and SAP also. Maybe I would gain a bit of cold start wear and tear protection with this mix?

I guess another way of asking the question would be: Is HTHS the most important spec to be concerned about generally, or am I missing something important?

Also, even though VW uses one spec for various gas engines, presumably to avoid marketing problems and consumer confusion, are there likely to be differences in the optimal HTHS viscosity for these different engines? I wish I had an oil pressure gauge.

 

[SubLGT]

Originally Posted By: pipo
.........Is this perhaps a prescription for fresh oil just before the start of the coldest months in cold weather climates?


Yes. See this paper from Infineum: "Assessment of Ageing Mechanisms in Lubricants and Their Effects on Retained Low Temperature Pumpability of Top Tier Oils"

http://www.infineum.com/Documents/Crankc...icants-2010.pdf

 

[SubLGT]

Originally Posted By: pipo
............I was thinking maybe 4 quarts of M1 0w-40 and 2 quarts of M1 0W-30, to keep the HTHS viscosity at about 3.5.............


DIY blending opens up a whole 'nother can o' worms!

 

[dparm]

My comment about it being "old" was merely that it isn't taking advantages of all the advances made in tribology and lubrication engineering we've seen since then. Older motors can still run it with confidence; newer motors that want API SM, for example, technically can't use it (though we have it in my mom's VQ35HR without any issues).

Years ago it was outstanding. Now I'd just call it "okay". For off-the-shelf it's still a very unique oil.

It's hard to pick it over M1 0w40 when they're both readily available and the same price.

 

[dparm]

Originally Posted By: pipo
Originally Posted By: Quattro Pete
M1 AFE 0w-30 may be a more modern formulation, but it was designed with a different purpose/target in mind: mainly improvement of fuel economy. If you need an oil meeting VW 502.00 spec (HT/HS of at least 3.5 cP), then M1 0w-30 isn't your oil.

As far as GC getting old comment, from what we know, GC's formulation hasn't changed since about 2004 or so. However, that does not necessarily make it bad. It is certainly still good enough to meet all the stringent German mfg specs. Also, we don't know for sure that GC's formulation hasn't changed. Not everything will show up on a $20 VOA... But most likely it's still the same.




I was thinking maybe 4 quarts of M1 0w-40 and 2 quarts of M1 0W-30, to keep the HTHS viscosity at about 3.5. Anything else about the M1 0W-30 that varies significantly from the 502 spec that I should be concerned about? I noticed that the TBN and SAP are a bit lower, so the oil might deplete faster, but I believe some of the other 502 oils have lower TBN and SAP also. Maybe I would gain a bit of cold start wear and tear protection with this mix?

I guess another way of asking the question would be: Is HTHS the most important spec to be concerned about generally, or am I missing something important?

Also, even though VW uses one spec for various gas engines, presumably to avoid marketing problems and consumer confusion, are there likely to be differences in the optimal HTHS viscosity for these different engines? I wish I had an oil pressure gauge.



But why even thin out the M1 0w40? It's great straight from the bottle. HTHS 3.8 gives you some "safety" over the 3.5 minimum.

If you are willing to mail-order/Internet-order, there's a whole world of other oils out there, such as 0w30s and 0w40s with very high VIs, HTHS of about 3.6, and extremely high-quality (group V) basestocks.

 

[SubLGT]

Originally Posted By: CATERHAM
...............Or what would be better is viscosity spec' at say 0C using the HTHS or MRV methodology. But there isn't so we work with what we're given...........


That would be very usefull, wouldn't it! After all these years, you would think someone at API or ILSAC would have proposed such an idea.