What's the GM-LL-25 Oil Spec?

[CosmicFlash]

Got an 03' Saab 9-3 SS and it states you can only use an oil with this spec and they go onto say that only the Saab 0W 30 Long Life Turbo Oil and Mobil 1 0W 40 meet the spec. They say it's a long life oil spec. Isn't ACEA A3 the same?

What are your thoughts on this? (BTW I'm new so sorry it this has been discussed before)

 

[Eiron]

Hi CosmicFlash,

Do a search on "GM-LL" & you'll find some previous info. Also, the VOA section has results from both of Saab's current OE oils & the M1 0W-40. I can tell you what I know from my research into this spec, but since GM refused to send me any info directly, some of this is deduction on my part.

In a nutshell, no, ACEA A3 is not the same thing. This new GM spec appears to have a fuel-efficiency aspect to it, so most A3 oils are too viscous to pass this portion. This doesn't mean A3 oils are unsatisfactory; in fact, M1 15W-50 will protect as well or better in your turbo engine than either the Saab 0W-30 or M1 0W-40. And Delvac 1 5W-40 combines the protective film of the M1 15W-50 with the additive package of the OE 0W-30. (But you wouldn't want to deal with the hassle of trying to educate your dealer or Saab Customer Assistance about it!)

Basically, it's requirement is an attempt to do two things:
1) Mitigate the problems created by using sub-premium oil in an oil-killing engine; part of the solution was to require only premium, fully synthetic oil via the spec, while the 50% increase in oil capacity & addition of GM's Oil Life Monitor handles the rest.
2) Earn GM more environmental credit $ by further reducing fluid waste products & increasing fuel efficiency.

In my opinion, M1 0W-40 should be the thinnest oil you should use in a Saab turbo engine.

 

[Primus]

OEM oil specifications are usually based on some API and/or ACEA primary performance criterias + own requirements taking into consideration specific engine design and expected oil intervals.

Interesting that oils qualified for GM LL-A-025 (gasoline engines) may be based either on performance criterias of ACEA A3/B3, or ACEA A1/B1 or A5/B5, but GM LL-B-025 (diesel engines) - only on A3/B3. Apparently, unlike B-025 oils, HT/HS required for A-025 is not very critical provided the oil meets other GM criterias. At the same time, most like GM has approved only those A1/B1 and A5/B5 oils which had HT/HS on the upper limit for these ACEA service fills, say 3.40-3.50.

Therefore, if it is not possible to find "original" oil, then it's better to use an oil approved for 1). ACEA A3/B3 + A-025 or B-025, 2). ACEA A3/B3/B4.

Difficult to say how strongly A-025 or B-025 oil differs from 1). and 2)., but one of the main distictions we can notice is lower ash content (1.0 %). Hope the links will help to take the right decision:

http://vectra.opel.com/brand_sites/vectra/launch/uk/en/downloads/pdfs/Vectra_oil_retailers.pdf

http://vectra.opel.com/brand_sites/vectra/launch/uk/en/downloads/pdfs/Customerinfo_oil.pdf