Why 10w30?
- Thread starter BigJohn
- Start date
Less VI needed so has better resistance to viscosity changes.
I've found that in older vehicles, sometimes on a cold morning I would get a puff of blue smoke on startup using the recommended 5w30 oil. Simply by using 10w30 wt, it all but stopped smoking. As far as starting goes, I notice no difference, unless your battery is on it's way out. Where I live it can range between 0-32f all winter. I've found that as my vehicles age and get up in mileage, their oil consumption tends to go up.It may be from wear, or just drip leaks. Using a heavier grade of oil usually is cures the problem alot cheaper then a motor rebuild.,,
Makes total sense and thanks for the explanations.
At the end of the of the day, Blenders and Stores pay attention to what is selling and they stock it.
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10w-30 is a great grade for down here.
Aside from this years freak winter storm, we see maybe 3-4 days a year below freezing.
There have been several years that I know we never got below freezing.
The decreased VI is one of the big reasons I like it, although it does not seem to be as much of a problem as it used to be since most oils base stock has improved in the past decade.
Only reason I don't use more of it is because it is rarely on clearance around here, and I have too much oil in my stash to pay full price for 10w-30.
Aside from this years freak winter storm, we see maybe 3-4 days a year below freezing.
There have been several years that I know we never got below freezing.
The decreased VI is one of the big reasons I like it, although it does not seem to be as much of a problem as it used to be since most oils base stock has improved in the past decade.
Only reason I don't use more of it is because it is rarely on clearance around here, and I have too much oil in my stash to pay full price for 10w-30.
Supposedly it was because they were higher in hths or more shear stable since it has less VI's. But with modern oils you can get equal or better hths, performance, and shear stability with a 5w-30 and a 10w-30 may be worse as a 5w-30 technically needs better base stocks but again modern oils are good enough to where a pure group 3 5/10-30 oil made by mobil states 20k miles.
in reality with modern oils it doesn't matter. some 5w-30's may be thicker than the same brand and lineups 10w-30 and may resist shear better. Back then yeah a 10w-30 in the same brand and lineup was almost guaranteed to be more shear stable as the inferiority of base stocks back then extrapolated it. Now it's a more guessing game with how blurred the lines are between the two especially in high end near pao group 3 and gtl base stocks. in group 2/3 oils it would be more pronounced.
in reality with modern oils it doesn't matter. some 5w-30's may be thicker than the same brand and lineups 10w-30 and may resist shear better. Back then yeah a 10w-30 in the same brand and lineup was almost guaranteed to be more shear stable as the inferiority of base stocks back then extrapolated it. Now it's a more guessing game with how blurred the lines are between the two especially in high end near pao group 3 and gtl base stocks. in group 2/3 oils it would be more pronounced.
I like 10W30, compared to a similar 5W30 made on the same type of base stock and with the same add pack, the 10W30 will have less polymer VII (viscosity index improvers) added to it than the similar 5W30.
Also the 10W30 will be more shear stable (less VII) and will have a lower Noack volatility (thicker base stock). As for cold starting a 10W30 is tested down to 0F (-20C), below that you need a 5W30 or 0W30.
I live in a warm climate so I can use 10W30 year round. Give me any more cold starting than that, and it’s wasted on me, so I would rather have the shear stability and low volatility instead.
Couple that viscosity grade, with the modern API SP & GF-6A specs, and you have a high quality oil that passes the the most recent LSPI protection requirements and the new timing chain wear protection test.
Also the 10W30 will be more shear stable (less VII) and will have a lower Noack volatility (thicker base stock). As for cold starting a 10W30 is tested down to 0F (-20C), below that you need a 5W30 or 0W30.
I live in a warm climate so I can use 10W30 year round. Give me any more cold starting than that, and it’s wasted on me, so I would rather have the shear stability and low volatility instead.
Couple that viscosity grade, with the modern API SP & GF-6A specs, and you have a high quality oil that passes the the most recent LSPI protection requirements and the new timing chain wear protection test.
Where is merkava, aka clyde, aka goldenrod when you need him?
OVERKILL
$100 Site Donor 2021
The idea is that the 10w-30 will be blended similarly and have less VII. That's likely not true. They can get away with using cheaper bases because of the narrower spread. I posted these two yesterday from Mobil, but they also appear to be germane to this discussion, so I will share them again:
5w-30 blended with Group II+ that meets DEXOS:
10w-30 HDEO blended entirely with Group II+:
5w-30 blended with Group II+ that meets DEXOS:
10w-30 HDEO blended entirely with Group II+:
Excellent question and excellent feedback. Thanks. I was wondering this too, and suspected it had to do with smaller number spread meaning more sheer stable and less reliance on additives, generally and simplistically speaking; making oil perform unnaturally (lower cold flow) requires some extra science magic.
up there yeah id definitely use a thicker oil than a 20 or 30 grade but the hths doesnt really get better beyond a 15w-40 like chevron delo which is 4.2 and can actually get worse.
i know that gtx 20w-50 is 3.7-3.8 hths so pretty bad for its viscosity. mobil's 15w-50 is 4.5 so its one of the few good off the shelf oils.
wemay
Site Donor 2023
Down here, 10W30 sells less than only 0W20.
Is it only that, I though the datasheet said more than 3.7 or 3.8 whatever the minimum HTHS for it is, I assume the actual is higher.
Is the difference due to being a SP rated PCMO vs a CK-4 rated HDEO?
Is there any chart showing 10w-30 PCMO formulation?
@wemay and I were just discussing ol' Merk a little while go. Him and Garak.
Regarding 10W30, We have PP Pure Plus 10W30 with it's low noack, in both our Kia Turbo's. Awesome stuff.
biggest advantage imho is the relatively high HTHS...
Mobil 1 10W-30HM HTHS is 3.5
Mobil 1 10W-30HM HTHS is 3.5
OVERKILL
$100 Site Donor 2021
No, not being a popular grade, it wasn't shown in the example formulations. They had two 5w-30's, a 10w-30 HDEO and 10w-40 HDEO.
However, they do provide this:
That shows you can blend a 10w-xx PCMO with just straight EHC 50.
yeah it states that gtx 20w-50 is 3.7 but the spec for an sae 50 goes all the way down to 3.5 as the minimum but delo 400 sde is 4.2.
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