ACEA A3/B3 vrs A5/B5

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Can anyone explain in layman terms the difference in ACEA A3/B3 vrs A5/B5 spec.
Is A3/B3 a longer life higher heat oil ?
Does A5/B5 protect as good ?
Thanks
 
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Better ?
Explain
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But more importantly, you should be running what your owner's manual suggests: it is one or the other, not both.

In general A3/B3 is a higher HT/HS viscosity than A5/B5, because A5/B5 has to meet fuel economy requirements and A3/B3 does not.
 

tblt44

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But more importantly, you should be running what your owner's manual suggests: it is one or the other, not both.

In general A3/B3 is a higher HT/HS viscosity than A5/B5, because A5/B5 has to meet fuel economy requirements and A3/B3 does not.

My truck is a 2003 with 186k, GM6094 spec 5w-30 or 10w-30 if in warmer climates.
I think Im ok running most any 5w-30 or 10w-30 will meet those obsolete specs.
 
A5/B5 is a spec mainly targeted towards fuel efficiency.
A3/B3 is A3/B4's older brother, they both have a minimum HTHS of 3.5 and are full saps with generally a good dose of antiwear and detergent additives.
Only difference between B3 and B4 is B3 requires a minimum TBN of 8 while B4 requires 10.

In Europe pretty much anything thicker than 5W-30 is either A3/B3 or A3/B4, except some really low cost oils.
 
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My truck is a 2003 with 186k, GM6094 spec 5w-30 or 10w-30 if in warmer climates.
Is there a reason why you're looking at ACEA oils? Are you going to be running extended oil change intervals?


I think Im ok running most any 5w-30 or 10w-30 will meet those obsolete specs.
Yeah, GM6094 is an outdated spec, if I'm not mistaken. Likely retired when Dexos was introduced. My guess is any 5w-30 oil would be fine, if you don't run extended oil change intervals. And if you do, I would think any Dexos1 gen2 approved oil would work fine, as would ACEA A5/B5 oil.
 

tblt44

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Is there a reason why you're looking at ACEA oils? Are you going to be running extended oil change intervals?


Yeah, GM6094 is an outdated spec, if I'm not mistaken. Likely retired when Dexos was introduced. My guess is any 5w-30 oil would be fine, if you don't run extended oil change intervals. And if you do, I would think any Dexos1 gen2 approved oil would work fine, as would ACEA A5/B5 oil.
Just looking at M1 HM 5w-30 & 10W-30.
5w 30 is A5/B5 and 10w 30 is A3/B3 and nether lists any other GM specs but Im sure they meet and/or exceed them
 
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Just looking at M1 HM 5w-30 & 10W-30.
5w 30 is A5/B5 and 10w 30 is A3/B3 and nether lists any other GM specs but Im sure they meet and/or exceed them
My guess is you'll be fine with either. The 5W-30 might give you marginally better fuel economy. Not sure if you'd actually notice it.
 
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It might be an oversimplified view of the world but I see A3 as applicable to engines that need a 30 Grade (ie 3.5 HTHS).
But most "30 grade" oils in the US actually have HT/HS viscosity below 3.5 cP due to fuel economy considerations.

Anyway, if you see "A3" as a 30 Grade oil, then what do you see "A5" as? :)

Just curious.
 
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Hey guys, I have an early 2000s naturally aspirated engine that called for 10W30 oil, under service API SJ.

Would an API SN+ oil today, with A3/B4 (0W30) or A5/B5 (5W30) be more suitable for use? As I understand there is no description in the car manual regarding ACEA requirements. Whilst xW30 oils with A5/B5 are very easy to find these days, the same cannot be said for the A3/B4 variants. Would the lower HTHS viscosities in A5/B5 be of concern?

What were the HTHS requirements in API SJ (if any) back in the day if you happen to know.

edit: I have been using a 0W40 with A3/B4 but thinking about using a 30wt oil. Summer all round on the tropics here so cold cranking is not a concern.
 
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In a nutshell no, I wouldn’t use a 5W-30 in an engine calling for 10W-30. For instance, the Nissan VQ and whatever engine was in the Honda S2000 both favored 10w-30. They were known for shearing down oil.
 
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In a nutshell no, I wouldn’t use a 5W-30 in an engine calling for 10W-30. For instance, the Nissan VQ and whatever engine was in the Honda S2000 both favored 10w-30. They were known for shearing down oil.
I'd rather run an ACEA sequence oil that has demonstrated stay-in-grade performance rather than guess that a specific grade would necessarily be more stable.
 
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SR5

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As Kschachn alludes to above, all ACEA oils are required to pass a shear stability stay-in-grade test, this test is not part of API and one of the reasons I like Euro oils.

My current ride, Nissan X-Trail (aka Rogue) is known to shear oil, so I’m running Castrol Edge 5W30 A3/B4 for just that reason.

However I do agree, if you are comparing two similarly formulated API & ILSAC oils from the same company, you would naturally assume the 10W30 is more shear stable.
 
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A3/B4 would be similar to a hdeo as compared to an A5/ B5 being a passenger car oil . Look at the additive package as in the uoas and also the HTHS is different between the two.
 
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