[AndyV7o]

Since recently joining the Volvo world and hanging around/interfering in here I have noticed a common theme (as is with pretty much any motoring forum) of confusion relating to oil. This is compounded by a whole 'generation' of Volvo's being 'out of step' with other manufacturers regarding oil specs, and the large amount of older vehicles around.

If you ever feel confused about oil, worry about what is right or wrong, want guidance or confirmation, then please read-on!

I decided to attempt to create a thread (hopefully sticky?) which would provide firstly the basic essential info, then some type specific info, followed by anything more complicated thereafter.
I must point out Im not an expert Tribologist (oil scientist) and reserve the right to look like a prat if anything is incorrect, but have spent hours upon hours over the last few years researching engine oil from anecdotal forum waffle to official documents and all-sorts inbetween.
It seems logical and feels nice to use this in order to help people.
Anything I write I believe wholeheartedly to be accurate and in no way misleading, but welcome any challenge or correction, and if anything is found to be incorrect then that shall be amended.
Unfortunately at present, knowledge of euro5 onwards or many engine specifics isnt known to me, so ill begin with what I do know and folk can hopefully help fill in any gaps.

So, lets begin with some basic specs.
A lot of Volvo vehicles 'simply' use Acea specs, these are a European set of benchmark, baseline specs. Most manufacturer specs begin with these and build upon them, but Volvo were happy to use as-is.

Acea 'A' classification is for petrol engines.
Acea 'B' classification is for diesel engines.
Acea 'C' classification is for vehicles (primarily diesel) with exhaust after treatment beyond a basic catalytic converter. We're usually talking Dpf's here.
The Acea class numbering is a little mixed and is the most common cause of mix-ups.
A1/B1 were earlier 'fuel economy' specs which are superceeded by A5/B5, and should only be used in an engine which is designed for them.
A3/B3/B4 are 'std' specs, B4 supercedes B3. These are perfectly safe to use in engines calling for 1/5 (that can be elaborated upon later)
A2/B2 are defunct.

Api specs are kind-of irrelevant, but do bear a little relevance which we'll get to later, but what we'll say for now is newer isnt necessarliy better.

Grades, 0w30, 5w40 etc... The first number is the thickness when cold (0w, 5w, 10w etc) the second is the thicknes when hot. Oil doesnt get thicker when hot, it gets much thinner. The second number relates to the equivalent thickness of a monograde oil at that temperature, which is still much thinner than the cold thickness of the lighter weight monograde equivalent. Thus 0w is thicker when cold than 40 is when hot. So, if your engine uses 10w40 and you switch to 0w40, its the same when hot, but much thinner when cold.
W means winter and refers to the first number. It doesnt mean weight or watt.
Synthetic oil is not thinner than semi or mineral, the grades dictate this. Synthetic does not make engines leak, or increase consumption.
Engines dont 'need' semi or mineral, just the additives often used in more traditional oils. Conversely, some engines do 'need' synthetic.
Ideally use the grade specified for the engine, and certainly from the permitted range for your climate. Don't go lower with the second number (ie dont go from 40 to 30) and only ever go one grade higher, if really necessary. Thicker oil does not directly mean more protection, it can hinder flow and cause excessive oil pressure overloading the pump amongst other things.

As some peoples eyes will already be glazing over, the first, most basic bit of info can now be offered.
If this so far is complicated enough for you, then you may follow the upcoming bit of advice and be comfortable you are doing OK by your car.
Check, double check, triple check the spec required for your particular engine/year and buy oil with this approval, don't get caught up in other specs.
The important thing, and the most prevalent area where people are going wrong, is do not use A5/B5 (or A1/B1) if your handbook does not ask for it. If in doubt here, use A3/B4. A3/B4 is sufficient for most engines from late 80's through to Euro4. Older engines want 'classic' oil designed to old specs (often with a modern twist) and grades. Modern oils lack necessary ingredients for old technology and can do more harm than good!
From what I have found so far, if your engine is Euro 3 or earlier, A5/1/B5/1 is not correct and thus should not be used. It does NOT supercede and is NOT superior to A3/B4. This alone is a large part of the whole reason for this thread!

If you've had enough now, thats it. You ought to be covered. Any questions just ask.


So, onto the first rung of the more technical ladder, a brief foray into the mostly irrelevant API specs which can build on the above offering the potential of better protection, and also where a lot of people probably ought to call it a day afterwards!

Earlier a brief mention was made of newer specs not always being better.
The other week somone on here was confused that Castrol edge had a 'lower' spec than Magnatec whilst being the superior product. The specs in question were Api.
Magnatec was SN, Edge was SL...
They go in alphabetical order thus SN is 2 grades 'higher' than SL. Api specs also are designated to be backwards compatible thus each new spec 'improves' on the latter.
So wheres the rub? Why was the edge an older spec than magnatec?
After much time trying to extract info from thin-air I found one key difference; Phosphorus levels. These indicate the level of anti-wear additives, usually zddp. Zddp is a thing touted by many to be a magic substance that makes an engine invincible. This isnt the case, but it is one of, if not THE most effective wear inhibitors of the traditional variety. It is reduced or replaced in more modern oils as it is also one of THE key killers of Dpf's and to a lesser extent cats. Its replacements however dont/cant cut the mustard in certain engines using certain materials, particularly cam followers. Knackered cam followers and camshaft isnt something you want!
So, it makes logical sense that the Edge, being a performance oriented top-tier oil cannot meet SN due to extra anti-wear additives beyond those permitted for SN. It also has less other modern specs than the magnatec, also telling that there is something in there that prevents these being met.
The magnatec is a more general lubricant for more general use, as such it meets a wider range of specs. The particular formulation of edge was based around the Acea specs, with the emphasis on performance without being 'clouded' by trying to do everything. Thus edge only meets SL -because- it is better than magnatec, even though it would appear on the contrary to most people.
So......
Following on from the Acea specs, the API specs can be used as a loose indicator of offering better protection.
Furthermore, Acea specs have updates, and the parameters can change. When Volvo were specifying A3/B4 & A5/B5 oils, the current Api spec was SL-SM. The parameters of A3/B4 & A5/B5 have changed a little since then along with the Api specs. A lot of oils today meet API SN and the later A3/B4, A5/B5 which isnt the same as originally specc'ed by Volvo.
If you wish to give your car the level of protection intended at the time it was built, without any modern eco-compromise reducing it, an oil of A5/B5 or A3/B4 meeting API SL is seemingly the closest you are going to ever get.



That will conclude that for now.
Really hope this helps people cut through the confusion, nonsense and hearsay!

What I will post next is some product info that may help people cut to the chase in sourcing some decent appropriate oil.