Oil types/grades/spec clarification

[volvoid]

The 4.2 V8 Audi petrol, bit thirsty that, VW state to use an "ordinary" oil and NOT the current spec for the current cars. Presumably for the reasons Andy has highlighted, load bearing - shear under load, etc.
Ive driven one, very fast, but not especially comfortable and no fun at all. Save yer pennies.

[AndyV7o]

The vw specs are a bit of an enigma, both 505.01 and 507 for pd engines are based on C3, but are supposed to be very strong regarding high loads with the camshaft/tappets/injectors, which suggests a 'magic' ingredient, however whilst asking a guy at Millers if they would be good enough to use in place of B4 in my Volvo (we have an octavia pd, itd be useful to be able to use one oil) he was very vague and simply said 'your engine asks for B4 which is full saps, so only use that' I pressed for a bit more info quoting the supposed compatibility of C3 and that vw build upon it, but just got a list of their oils which meet B4 and told to use those. He may just be protecting their liability, it may be that he feels their oil might not be strong enough but obviously wouldn't say that, it may be that C3 based oils even for pd engines still arent strong enough (and that the pd requirements are exaggerated), I dunno. Was talking to a guy at Total who said 'lets try and find a mutually compatible oil, get back to me with specific info of the cars, look forward to hearing from you', I replied, and heard nothing more! I don't like to pester tech people who arent there for needy customer support, so I left it be...

[volvoid]

the only people who really know are those design engineers who specced the oils requirements and those who formulated the brews. Few of each, and no-ones giving any secrets away. I doubt the sales technicians we get to speak to ever really know whats in a brew.

[volvoid]

I do know that the indeopendant garage down the road from me bulk buys a "very good oil" which does a lot of cars, but they also check the specs of any car and get in whatever is needed.
I hope that snippet is of use to someone

[AndyV7o]

64000 dollar question - would a 0-30 kill the engine, and if so, how? Am interested to better understand, if possible.
*referred to this thread by another member*
Yes, I've read a good deal about oil, including that, but it doesn't answer my question as to whether a 0-30 would be deliterious to an engine which specced 0-20. Any thoughts on that?
Hypothetically putting aside all the other oil specs, I can't see how the slightly thicker oil would be directly damaging to the engine, but it would put greater load on the oil pump drive and so damage the fuel economy.

Answer:
It largely depends on the particular engine and oil.
If you read in *this* thread noting talk and behaviour of the HTHS values...
The 0w20 volvo/C5 spec is exceedingly light, if you were to use a C2 0w30 youd probably get away with it ok, a B4 spec 0w30 would/could cause excessive oil pressure and reduced flow starving the engine of oil. The saps of the spec also need to be considered, too low=engine wear, too high=dpf death (figuratively speaking)
Its not simply about xW xx in this day and age.

'I used to run Prii, where 0-20 was specced as part of the drive to lower internal friction and improve efficiency.'

Answer:
Its the drag which is reduced, and the base oils used/needed to make these oils by nature tend to have a better film strength if the crank journals etc manage to push through the hydrodynamic 'cushion' of oil. Its not friction which is lowered per-se (though of course drag is largely down to onternal friction within the oil itself)



The thing is, engines designed for these light oils have exceptionally tight tolerances in order to use them, which makes them even more intolerant of incorrect viscosity/hths

[volvoid]

So, for modern engines especially, are we saying -
use what the manufacturer says.

As has been pointed out a few times this week, the FULL spec of the oil has to understood if one is to buy outside of the approved list.

Do the manufacturers make their lists of approved oils readily available to the public ? I feel that they should, and in years to come they must.

I cant find any.

[volvoid]

It is hard to find some of these very high spec oils, but will get easier as demand increases. There was a time when multigrade was a very big deal.

Perhaps its an idea to at least keep a note of the oil spec in the car - eg
0w20 C3 A5 B5 volvo xyz123

sometimes when Im in a long queue at a petrol station I'll browse the overpriced oils on sale, often thay have the common ones but nothing suitable for VW PD, hardly a rare engine. Perhaps we shoud all kep a small bottle in a cubby hole, or at least cheack our oil levels occasionally.

[AndyV7o]

Its my view that a cars boot should always contain some oil for top-up!
Yes there are lists available, some make specific forums have them kicking about...
As you say the specific specs are becoming predominant, and if one is to deviate at all one must understand the fundamentals if they wish to preserve their engine and dpf etc.
In the old days it was static viscosity, if your engine took 15w40 you used that or maybe 10w40, it was that simple. Now you've got to get the right string of letters and numbers on the label, and remember said string, which could appear on varied viscosities or one specific viscosity, and which will oly appear on certain bottles but not others in the same viscosity.......

[AndyV7o]

If it floats anyones boat, Ive been playing with a spreadsheet...
For the D5 euro 3
I picked the better/most suitable oils from the previous list, to see what comes out as most appropriate. Although the Edge 0w30 A3/B4 (which is the closest to factory fill and was Volvos recommendation for these engines (afaik)) is no longer available to buy (though castrol seem to still make it) it has been included as a benchmark for comparison.
Further to this I then separated out those with the closest fundamentals, lower in the table.
3 oils are very close indeed to the edge, and would make ideal candidates for a healthy engine. They are very very strong oils too. These are Fuchs Titan Supersyn Longlife 0w30, Mobil 1 FS 0w40, and Petronas Syntium 7000 0w40. The Shell Helix Ultra comes within an ace, and is still an exceptional oil for these engines.

Any values I couldnt find are substituted where possible with the spec requirement value.

[AndyV7o]

Since Ive had all day to dwell on it (and clearly fancy a public conversation with myself ) I though I might expand on the above.
The info in the table tells a few things, which indicate certain qualities.
For:

Nearest to factory fill/manufacturers choice/benchmark
Syntium 7000 0w40
Quartz 9000 0w30

Tappet/ cam protection (higher zddp levels)
Supersyn LL 0w30
Quartz 9000 0w30

Fuel economy (lower hths and cold viscosity, excellent base oil(s))
Supersyn LL 0w30

Long drain intervals (higher tbn)
M1 FS 0w40

Cold starts (lower cold viscosity, higher VI)
Supersyn LL 0w30
Quartz 9000 0w30
M1 FS 0w40

Worn/noisy engine (thicker viscosity and higher hths, preferably higher zddp)
Supersyn 5w40
8100 Xcess

High rpm / harsh driving protection (higher hths, excellent base oil(s))
M1 FS 0w40
Helix Ultra 5w40
8100 Xcess

Or any combo of desired behaviours...