Difference between A3/B3 and A3/B4?

[1JZ_E46]

Can someone please explain to me the difference between A3/B3 and A3/B4? Most "euro" oils contain both specifications, however, in looking at high-mileage oils, Castrol EDGE High Mileage 10W-40 is A3/B4 while Mobil 1 High Mileage 10W-40 is A3/B3. Is one specification better than the other? Thanks guys.

Edit: I did search the forum, but couldn't find any definitive answer.

 

[mightymousetech]

A3/B3
https://www.lubrizol.com/Lubricant-and-F...es/ACEA-A3B3-10

Quote:
ACEA A3/B3 oils are Mainline lubricants. They are designed for general usage use in a wide range of gasoline and light duty diesel engines. ACEA A3/B3 oils are typically used in older vehicles as they do not provide the minimum performance demanded by the latest OEM specifications.


A3/B4
https://www.lubrizol.com/Lubricant-and-F...es/ACEA-A3B4-10

Quote:
ACEA A3/B4 oils are Upper Mainline lubricants. They are designed for a use in high performance gasoline and light duty diesel engines and are typically used in newer vehicles as they provide the minimum performance demanded by many OEM specifications.


A3/B4 is a much higher specification.

 

[wemay]

 

[Quattro Pete]

A3/B3 has a TBN minimum of 8.
A3/B4 has a TBN minimum of 10.

 

[1JZ_E46]

Originally Posted By: Quattro Pete
A3/B3 has a TBN minimum of 8.
A3/B4 has a TBN minimum of 10.


Where do you find EDGE HM 10W-40 for less than $10 /quart? Did it solve any oil burning or leaking issues in your 530?

 

[SR5]

Originally Posted By: Quattro Pete
A3/B3 has a TBN minimum of 8.
A3/B4 has a TBN minimum of 10.

Yes as QP says, the most obvious difference for PCMO application is TBN with A3/B4 having the higher value. Otherwise they are both high SAPS, high HTHS (>3.5 cP), Euro grade oil.

In M1 speak, the A3/B4 would be the EP (extended performance - longer OCI) version.

If you qualify for A3/B4 you also qualify for A3/B3 and so can claim both, but not the other way around. I think they put the lesser spec (B3) on the higher spec (B4) just to help those shopping, who don't know the difference and are looking for what is in the owners manual, most likely with an older car. I can't see any reason for a modern Euro car to spec B3 now days when B4 is everywhere. However Europe seems to be going for the mid-SAPS C3 oil as their standard spec oil now days, which is pretty much what the GM Dexos2 (high HTHS) oil seems to be based on.

Some API SN oils also say they qualify as SM and SL etc. Same thing as saying a B4 oil also qualifys as B3. It's more to make it clear to the customer.

 

[Quattro Pete]

Originally Posted By: 1JZ_E46
Originally Posted By: Quattro Pete
A3/B3 has a TBN minimum of 8.
A3/B4 has a TBN minimum of 10.


Where do you find EDGE HM 10W-40 for less than $10 /quart?

Advance Auto Parts sometimes has it on sale for $5.50/qt.

Quote:
Did it solve any oil burning or leaking issues in your 530?

Oil burning may have reduced a bit. Leaking - not so much.

 

[1JZ_E46]

Originally Posted By: Quattro Pete
Advance Auto Parts sometimes has it on sale for $5.50/qt.


Thanks. I'll keep a look out for it.

Just curious, any reason why you don't use Mobil 1 High Mileage 10W-40? Seems to be more readily available and cheaper since WM stocks it in 5 quart jugs.

 

[Quattro Pete]

Quote:
Just curious, any reason why you don't use Mobil 1 High Mileage 10W-40?

It does not meet ACEA A3/B4, which is what I was looking for.

I was trying to find an HM oil that is not too far off from BMW's LL01 spec. The LL01 spec uses ACEA A3/B4 as baseline. But if you don't run very long OCI, it probably does not matter much.

 

[1JZ_E46]

Originally Posted By: Quattro Pete
Quote:
Just curious, any reason why you don't use Mobil 1 High Mileage 10W-40?

It does not meet ACEA A3/B4, which is what I was looking for.

I was trying to find an HM oil that is not too far off from BMW's LL01 spec. The LL01 spec uses ACEA A3/B4 as baseline. But if you don't run very long OCI, it probably does not matter much.


That was my assumption. I am "old-school" in that I only run 5k intervals, so a TBN of 8 vs 10 really isn't relevant. If I can't find the EDGE on sale at AAP by the time my next oil change is due, I'll go with the M1. Also, from what I have found on this site, M1 has higher anti-wear additives compared to the EDGE (900-1,000 compared to ~750).

 

[Quattro Pete]

Quote:
Also, from what I have found on this site, M1 has higher anti-wear additives compared to the EDGE (900-1,000 compared to ~750).

Edge uses more boron, which is anti-wear additive. Both oils have a decent amount of phosphorus and zinc which are also used as anti-wear agents. I made a quick comparison here:
https://bobistheoilguy.com/forums/ubbthr...ge_#Post4251474

EDIT: And of course Edge also includes titanium which Castrol is touting as a protective agent. Of course that could be mainly marketing mambo jumbo.

 

[1JZ_E46]

Originally Posted By: Quattro Pete
Edge uses more boron, which is anti-wear additive. Both oils have a decent amount of phosphorus and zinc which are also used as anti-wear agents. I made a quick comparison here:
https://bobistheoilguy.com/forums/ubbthr...ge_#Post4251474

EDIT: And of course Edge also includes titanium which Castrol is touting as a protective agent. Of course that could be mainly marketing mambo jumbo.


Nice comparison. The detergent add-packs are very different. Not sure if I like M1's... it's very different than any other LL-01 oil I've seen. All LL-01 oils I've seen are high calcium, low magnesium, with about 750-1,000 each of Zn and P. Leaning towards EDGE, if I can find it (my sump holds 9 qts! plus a couple for top-offs

)

 

[SonofJoe]

The difference between an A3/B3 10W40 and an A3/B4 is actually quite a lot.

First off, the 8 vs 10 TBN thing is the most visible difference but in reality it's probably the least significant. The imposition of higher TBN was politically driven to differentiate these oils from Low SAPs oils.

To meet both the ACEA B3 & B4 specs, engine oils must be put through their paces on the 60 hour VW TDI diesel test. Without getting overly technical, a B4 oil must leave the pistons cleaner with less ring stick. To achieve this, you generally need to put more Ashless Dispersant in a B4 oil.

Now all things being equal, putting more Ashless in an oil, increases it's Noack volatility. The 72 hour Peugeot TU5 test that you need to pass for ACEA A3 doesn't like high Noack. So a B4 oil, with higher levels of ashless, typically needs more synthetic base oil in the mix to bring the Noack back to something that is acceptable to the TU5. This extra synthetic directionally reduces VII loading (which is a good thing).

So, relative to an A3/B3 oil, an A3/B4 10W40 will contain...

...more metallic detergent (for TBN)
...more ashless dispersant (for Tdi)
...more Group III (for TU5)
...less VII polymer

Although much of this primarily manifests itself as better performance in diesel engines (with no PDFs), the oil will also be better for gasoline engines.

However, expect the A3/B4 10W40 to cost more..

 

[zeng]

Thanks SoJ.
Strictly in terms of requirements of testing sequences , can the same be said of that a A3B4 SN/SM has similar advantages comparing against SN/SM oils ?

 

[SonofJoe]

Originally Posted By: zeng
Thanks SoJ.
Strictly in terms of requirements of testing sequences , can the same be said of that a A3B4 SN/SM has similar advantages comparing against SN/SM oils ?


A pure SM/SN oil will not have been tested & proven in any diesel engine tests. As such, these oils tend to be lacking in Ashless Dispersant.

Although it's not absolutely the case, it fair to say that an A3/B4 will give you SM/SN 'for free' but the reverse is NOT true.

So yes, an oil that claims SM/SN/A3/B4 will have the listed advantages over a pure SM/SN oil.

 

[SR5]

Quote:
So, relative to an A3/B3 oil, an A3/B4 10W40 will contain...

...more metallic detergent (for TBN)
...more ashless dispersant (for Tdi)
...more Group III (for TU5)
...less VII polymer


Thanks Joe, I always enjoy reading your posts.

What you say certainly makes sense when picking between 10W40 semi-synthetics, the A3/B4 is the better pick. Over here all our 10W40's are A3/B4 anyway, and some like Shell also carry some OEMs like MB 229.3 and yes all carry SN as well.

To me the big choice is a full synthetic 5W-40 A3/B4 (probably Group III) or a mineral 15W-40 A3/B3 (probably Group II). These are the two most common 40 grade offerings around here and both are also SN.

Now apart from price, which is a significant difference, and TBN. The Group III will have a higher natural VI, but it's a 5W product. The Group II will have a lower VI, but it's a 15W. So which would carry the higher VII load ?

The A3/B4 has to pass Tdi with cleaner pistons, but it's a Group III oil. The A3/B3 has a lower Tdi clean piston requirements, but it's a Group II. So which needs more ashless dispersants ?

Which would you expect to have the lower Noack ?

My confusion is that in my market, the higher spec A3/B4 goes with the higher quality base (Group III) and the much higher price tag. The lower spec A3/B3 is always a mineral oil for me and much cheaper. But if I'm doing reasonable OCI's like 6k miles on the mineral and 9k miles on the synthetic, I suspect I may be getting more oil for my money buying the cheaper mineral oil. The mineral is easily have the price of the synthetic, but is it half the oil ?

 

[SonofJoe]

SR5,

It's been a while since I checked these things but I'd say the 15W40 Group II would contain less VII polymer than a 5W40 Group III. I'd also say the 5W40 contains more ashless to cope with the higher amount of VII. Finally my guess would be the 15W40 would have the lower Noack.

You didn't ask the questions but the 5W40 would give better fuel economy on short trips (but not on long highway jaunts) and would also be more susceptible to shear.

IMO, provided you change it out at a reasonable OCI, the Group II 15W40 would be more sensible oil choice.

PS - the 15W40 oil might be labelled as A3/B3 but there's a decent chance it actually meets the engine test requirements of A3/B4 (not the TBN). It's common industry practice to 'under claim' on cheap oils because oil companies want you to pay more for the nominally better product.

 

[1JZ_E46]

Wow, ask and you shall receive! Thanks for all the knowledge joe.

 

[1JZ_E46]

Also:

I reached out to Mobil Oil to see if they would provide a NOACK figure for their M1 HM 10W-40 as it would be going in a BMW which specs a max of 10% (LL-01). Mobil stated the NOACK is 7.6%. That's a respectable figure, and its consistent with what SoJ was explaining.

 

[wemay]

Thanks Joe!