ACEA A3 questions

[Eiron]

moribundman,

Another explanation might be that most Euro engines are now expecting Full Synthetic as the standard fill. When dino was de rigueur, the best way to insure the best protection and longest life was to require the improved durability A3 oils offered.

When you figger there's more pressure on car makers to increase gas mileage while reducing fluid replacement frequency, it's obvious you'll end up using thinner syn oils. ("Not that there's anything wrong with that!") I think an A3 syn could go quite a bit longer OCI than an A1 syn, simply because it's got to hold up to HT/HS better to get the A3 rating.

[ October 04, 2004, 06:49 PM: Message edited by: Eiron ]

 

[Tones]

Schaeffer's 30 weights meet the A3 rating.

As I understand it, the higher HTHS requirement of the A3 is an indicator of an oil's ability to stay in grade longer without shearing down.

 

[Palut]

Thanks for clarifying that moribundman. That had me a bit confused.

 

[moribundman]

quote:

---

Maybe they are concerned about oxidation thickening. If you have a shear stable oil this can be a problem. Ask Amsoil.

Gene

---

Good point and at least somewhat supported by the fact that the A3 spec limits how much an oil may thicken. However, I'm sure this is also part of the other ACEA specs.

Also, A3 and extended drain are not mutually exclusive. For example, Mobil 1 0W-40 meets A3, but also BMW LL-01, Opel Long Life Service Fill GM-LL-A-025, Opel Diesel Service Fill GM-LL-B-025.

Oh, and there are plenty 0w30 oils that meet A3.


Here are again the ACEA ratings:


Gasoline Sequences

A1 Oil intended for use in gasoline engines specifically designed to be capable of using low friction, low viscosity oils with a High Temperature / High Shear Rate Viscosity of 2.6 to 3.5 mPa.s. These oils may be unsuitable for use in some engines. Consult owner manual or handbook if in doubt.
A2 General purpose oil intended for use in most gasoline engines with normal drain intervals, although it may not be suitable for some high performance engines.
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.
A4 Reserved for future use for gasoline direct injection engines.
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.

Light duty diesel Sequences

B1 Oil intended for use in car and light van diesel engines specifically designed to be capable of using low friction, low viscosity oils with a High temperature / High shear rate viscosity of 2.6 to 3.5 mPa.s. These oils may be unsuitable for use in some engines. Consult owner manual or handbook if in doubt.
B2 General purpose oil intended for use in most car and light van diesel engines (primarily indirect injection) with normal drain intervals, although it may not be suitable for some high performance engines.
B3 Stable, stay-in-grade oil intended for use in high performance car and light van diesel 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.
B4 Stable, stay-in-grade oils intended for use in cars and light vans having direct injection diesel engines but also suitable for applications described under B3.
B5 Stable, stay-in-grade oil intended for use at extended drain intervals in car and light van diesel 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.