A3 and A5
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A5 Stable, stay-in-grade oil intended for use at extended drain intervals in high performance gasoline engines designed to be capable of using low friction, low viscosity oils with a HT/HS of 2.9 to 3.5 mPa.s. These oils may be unsuitable for use in some engines. Consult owner manual or handbook if in doubt.
A3 Stable, stay-in-grade oil intended for use in high performance gasoline engines and / or for extended drain intervals where specified by the engine manufacturer, and / or for year-round use of low viscosity oils, and/or for severe operating conditions as defined by the engine manufacturer. HT/HS >3.5
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Some engines are designed specifically for A5, and some shouldn't use it at all. And yes, A5 (and A3) is a much more stringent spec. than A1. I wouldn't call A5 a "cop-out" at all - just different.
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quote:That seems to be the case. Just yesterday I found an interesting article on A5 on some oil manufacturer's site. I think it was a European Shell or BP site. Anyway, they mentioned there was not yet an engine that required A5 spec oil. They were talking about how A5 combined long drain, fuel economy, and engine protection. I think A5 spec oil is lower HT/HS that A3. That should be one of the reasons why A5 spec oil would be a poor choice for an engine that requires A3 spec oil. [ August 01, 2003, 02:01 PM: Message edited by: moribundman ]
Some engines are designed specifically for A5, and some shouldn't use it at all. And yes, A5 (and A3) is a much more stringent spec. than A1. I wouldn't call A5 a "cop-out" at all - just
The A3 spec is no "better" than the A5 spec or the A1 spec. That's like saying 40-weight is "better" than 30-weight. Each category has different requirements specific to the category. An A5 oil can't meet the A3 spec and neither can an A3 oil meet the A5 spec.
All the ACEA categories are held to the same wear and deposit standards.
quote:Vettenuts, Unless it is not yet reflected on their website, I don't believe they are actually A3 rated; what the website says for Series 2000 20W50 and Series 3000 5W30 is "Recommended for Applications Requiring the Following Specifications." Note it doesn't say the oil has been formally submitted, tested and approved. It just says their oil is up to the requirements embodied in the various API, ILSAC and ACEA tests.
Originally posted by vettenuts: I seem to remember that Amsoil just got rated as A3, is this correct?
If you look at the ACEA standards from the viewpoint of an engine that needs an A3 oil then yes, A3 is the "highest" standard. But that's purely a subjective viewpoint.
My car engine was "specifically designed to be capable of using low friction, low viscosity oil", so from my viewpoint A1 or A5 is the "highest" standard. These categories must meet the same wear and deposit standards as A3 plus they must meet or exceed a strict fuel economy standard that A3 oils aren't required to meet.
Remember, these are minimum standards for each category. Just like API has. However, just because your car says it's acceptable to use A1 or A5 oils don't mean they're the best either.
We need to be objective here. An oil designed for "fuel economy" is just that....thin enough to make a fuel economy difference between the control 15-40 grade. You can look at it as CAFE. Same engine...in the U.S. the recommendation is 5-30 all year...and for the rest of the world the recommendation is 5-40,15-50, 15-50 or any other combination....why? Because your "best" category is not acceptable under higher load/stress conditions that are seen in certain parts of the world where CAFE is not applicable.
We can even further the point and talk about differences in A3 oils. Why does BMW use a 10-60 in the M3/M5? Ferrari? Because even though there are 5-30 that are in the better rated A3 category (no, not M-1 5-30), they can't cut the mustard when it comes to protection. So viscosity is important even though newer technology allows for thin 0-30/5-30 A3 oils to exist. ie. you can't have fuel economy and maximum protection at the same time.
Question to ask is whether you need the added protection...and that's the difficult one to answer. We've all heard about wear and piston slap by using A1/A5 rated M-1 TS 5-30. The best?
The statement that kills me is the "may be unsuitable for use in some engines". What does that mean? Does it mean it's OK to use it (aka U.S. 5-30) in disposable U.S. cars (because the poor sap customer will buy a new car at 100k = end of warranty) but, not in higher-end European engines? Weird....
Yes, the A5 is a cop-out, middle of the row rating. Better than A1, but not as good as A3. The only difference between A1 and A5 is A5 has "extended-drain capable". Seems like any API oil can be A1, Mobil 1 0,5,10-30 (aka U.S. synth's) are A5...and then Euro. 0-30, 5-30's and 40 and 50 weight synths are A3.
I seem to remember that Amsoil just got rated as A3, is this correct?
quote:That's probably my main beef with Amsoil from a marketing standpoint. They only submit a couple of their oils for API testing, and none (to my knowledge) for ACEA testing. Yet they pull this wishy-washy marketing BS lingo "Recommended for applications requiring blah, blah, blah..." It's misleading, because it does in fact lead a lot people to believe that the oil is actually ACEA rated when it's not.
Originally posted by pscholte: Unless it is not yet reflected on their website, I don't believe they are actually A3 rated; what the website says for Series 2000 20W50 and Series 3000 5W30 is "Recommended for Applications Requiring the Following Specifications." Note it doesn't say the oil has been formally submitted, tested and approved. It just says their oil is up to the requirements embodied in the various API, ILSAC and ACEA tests.
Dr. T is right. In some cases you need a stronger oil. I don't like the fact that M1 is not A3 rated. I just noticed that Autozone was carrying both the German Syntec 0w-30 and regular side by side. I'd like to know if this oil will stick around. If not, I'm going with S2k A3 rated oil in my next car.
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