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Ahhh there might lie what my answer was to above. So is the Mobil 1 0W-40 just something that stands out and doesn't necessarily follow the traditional guides as you put them there?
Why would you ever want to run 10W-30 over 5W-30?
- Thread starter Stopsign32v
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Ahhh there might lie what my answer was to above. So is the Mobil 1 0W-40 just something that stands out and doesn't necessarily follow the traditional guides as you put them there?
"All other things equal" I think it would be more durable. But the problem is things are never equal. And the fact that 10w30 doesn't need to meet any approvals means it just costs less to produce to get the same result as a 5w30.
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So you guys are saying https://www.walmart.com/ip/Mobil-1-...2?classType=VARIANT&athbdg=L1103&from=/search is the bee's knees and this is what they run in racing, etc?
Edit: I see the NASCAR logo!!!!
Edit: I see the NASCAR logo!!!!
no it follows the same rules, but the bigger spread usually translates into a higher viscosity index, and that's what's in play above freezing
I would think they run a racing oil in racing, it would be more effective in keeping wear down, but won't last 15k miles, or even 5k miles.
Yeah if buying Amsoil signature series for summer use I would likely pick 10w30 knowing that in this case it's likely the more durable option. But in typical m1, Pennzoil etc OTC options usually a 0w40 is the best option because of the approvals it needs to meet.
It's about approvals, licenses and certifications. And M1 0W-40 is loaded with them, with the extra benefit of being blended with "cutting edge" base oils and add packs. All for a very low price.
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I think this might be the next oil I use.
I do wonder though, how long until Mobil changes it to something less spectacular.
It has been changed a couple of times including very recently....but it still meets those approvals.
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Been researching all day. I think I will be going with the Mobil 1 0W-40 European Formula
Yep and I’m not certain the SP formula was an improvement.
the SP-GF-6a is a improvement depending on the vehicle, and viscosity requirements for mostly newer cars & of course the CAFE ,EPA requirements of modern formulated engine oils in USA , the euro oils have different standards that address the longtivity of the engine performance and oci in a better way in certain applications. by no means will a SP-GF-6a oil give poor performance. there are some oil company's that do not have various licenses and approvals, perhaps due to cost of testing or not interested in doing so, if that's the case let the buyer be cautious on use unless purchased by a company of good reputation.
Thanks. I figured. The previous formula with some ester was highly regarded. Even Dave from HPL made mention. I’ve switched most of my fleet to ESP 0w30 which is close to the previous base oil formula.
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Patman
Staff member
Long term members here might remember me stating many times in the past that I felt like 10w30 was an obsolete viscosity and now more than ever I feel like that is true. The 5w30s of today are just that good that there really isn’t a big reason to choose 10w30 anymore. Same with 10w40 for that matter…
this is true the 5w-30 synthetic oil can accomplish what a 10w-30 does for the most part if not all ,the trend to more lower viscosity oils like 0w-20 ,0w-16 is the current wave, and even lower viscosity's ,,the triboligists and formulators are doing a fantastic job keeping up with the engine manufactures and gov regulations in whatever the requirements are at a modest price point. & looking forward with anticipation to the new SQ, GF-7 oils maybe even more of a game changer.
I agree with you that a modern 5W30 can be made to a very high standard, look at Castrol Edge 5W30 A3/B4 with BMW LL-01 & MB 229.5 and you can get this stuff everywhere often at very good prices.
Still the big name manufacturers could, but don't, make me an even better 10W30 on an equivalent 5W30 formulation running slightly thicker base stock. More shear stable and lower volatility. This would also meet BMW & MB quality specs, but can't get formal approval because these OEM specs are locked to fixed viscosity grades. The OEM rules effectively lockout 10W30 as a grade. I can see why, for non oil nerds, just look for the logo / spec like Dexos or MB and it will work fine in both hot and cold climates. It saves confusion when writing a world spec.
However for people like me who live in a warm climate and could run 15W40 year round, I would prefer more high quality 10W30 oils. At least ACEA is viscosity grade independent.
Still I know it's never going to happen. Not commercially viable. Hence why I buy Edge 5W30 A3/B4.
Thanks!
This is a big improvement and definitely worth having these lower Noack volatility %.
Given that you don't live in a cold climate and need the extra 5Wx cold starting ability.
To me, all things being equal, you should have as much cold starting as you need, but no more than you need.
Of course, as many have already pointed out, for most manufacturers, all things aren't equal and the 10W30 can be a cheaper blend. It's good to see that Amsoil is producing high quality products for all viscosity grades.
Carlostrece
$100 Site Donor 2025
In a warm climate it doesn't matter as much, but it still matters some. Also, even Southern states have some cold days when it matters more.
So 5w30 is always an improvement over 10w30 in modern times (because 5w30 is now perfected and shear stable enough in hot weather). IMO
20 years ago I'd agree 100%. That did used to signifigantly be the situation 20+ years ago. In modern times 5w30 is so good that it's a non-issue now.
To expand on that... Way back in the day there was 10w30. I don't think 5w30 existed yet or was uncommon. Then some years went by and both were common, but 5w30 was still a young product while 10w30 was already perfected. At that time 5w30 was only recommended for cold climate winter use. 10w30 was for moderate and hot climates.
At that time I had a conversation with a Chevron oil executive. She told me I should use 10w30 in my Jeep 4L and Buick 3800 because 10w30 was recommended by the car makers for my moderate climate.
She said 5w30 was (at that time) only good for cold winter use. She said 5w30 wasn't shear stable enough for use in hot summer weather, but 10w30 was. Meaning 5w30 would quickly deteriorate in hot weather. 5w30 and 10w30 were both fine for fall and spring.
She also said 0w40 was not stable/durable enough for use in hot weather. At that time 0w40 was only for artic winter conditions in vehicles that would normally use 10w40 or 15w40. I'm not sure if 5w40 existed at that time.
That was 25-30 years ago. In modern times, oils are a lot better than they used to be.
Now I use 5w30 year-round with no worries because it's become very good and shear stable (even in hot weather). This makes 10w30 pretty much obsolete today, except maybe for some severe diesel applications in summer. IMO.
We could still have a debate about whether 0w40 has become shear stable enough for year-round use in hot summers. I still think "no thanks" to 0w40 in hot summer. I do now like 5w40 for year-round use in engines where 5w40 is appropriate.
I'm using 5w30 year-round in my Buick 3800. I stopped buying 10w30 about 10 years ago when I became aware that 5w30 had been perfected. Though in reality, 5w30 might have already been perfected 15 years ago. I think it took me 5 years to realize 5w30 was perfected and 10w30 had become obsolete for old 90s and early 2000s gas cars in most climates.
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10W30 has often been touted here specific to GDI engines and reduced intake valve deposits (less VII’s used) . That said , with the greater popularity of 5W30 , newer specs , better base stocks being developed , etc. how long before 10W30 becomes an oil that no longer has any significant benifit over 5W30 - even for GDI engines ?
