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Here is a part of the « proof » requested earlier on this forum about the VW 508 spec if the only driver is in fact fuel economy and if it includes other specific performance requirements.
See links above. The answer is pretty clear comparing VW 508 and VW 504 requirements from Lubrizol: the only difference is a lower HTHS...for fuel economy, all others requirements are identical. A quick search will reveal the the point in using lower HTHS is reducing fluid motion internal friction.
Take away: any VW 504 approved lubricants satisfies performance requirements by VW 508 specced engine....except HTHS viscosity, which is for fuel economy.
The only disagreement remains about the viscosity grade (VW 504 = xW-30 vs VW 508 = xW-20), but we already trade a lot of comments and FAQ to allow one to make his/her head around this.
I didn't see anything in their webpage that discusses the actual test procedures required to meet either requirement. The pages you linked had just some very basic physical properties. No test procedure values and a ton of other properties not listed. Even viscosity actually. Maybe i overlooked it?
With audi requiring 0w20 its annoying if its purely fuel economy which it may be. I just wish there was solid info on the test sequences each are having to meet and if 508 isnt able to meet the same itd be great if vw/audi would clarify if going to 504 is acceptable for severe duty.
Yes, the 30W oil is ‘thicker’ at 100C than the 20W oil. The 20W oil thins out more quickly at 100C. That tells me the oil pump has to work a little harder to move the 30W oil at 100C.
The latest discussion on this thread has been an Engineer’s dream. A couple of guys debating oil properties in such minute detail that the average person can’t comprehend. If anyone really believes that using a 0W-30 oil in their Audi spec’d for 0W-20 is going to break the engine, then go buy a BMW. As Nick has implied, I am sure the engine and its components are spec’d for a much wider operating range than any difference between these two oil grades would allow.
Now whether or not Audi will honor your warranty on an oil related part failure if you are not running the required oil is a completely different matter.
1- how oil behave: with an increase of temperature, viscosity decreases and vice-versa.
2- 0w-20 thicker than a 0w-30? Of course, a 0w-20 at -20 celcius will always be a lot thicker than 0w-30, 5w-30, even a 10w-40 (and so on) at 100 celcius. See point 1 for oil behavior in regard to temperature.
My point was: if your engine can handle a thick, cold 0W-20 at startup, it can most likely handle a thin, hot 5W-30 at operating temperature. Well, it’s true that conditions differs between cold startup and highway (RPM, load, etc) but I just wished to put things in perspective about the risk to use a slightly heavier oil viscosity grade than recommended. Oil viscosity inside your engine varies all the time with temperature.
Question. The statement in your post that states 0-20w will be WAY thicker than 0-30w at operating temperatures does not appear to align with how oil behaves. Can you clarify?
He's comparing a cold 0w-20 against a hot 0w-30, for some reason.
If you want to know the visc of any oil at any temp, just punch it into the calc link I shared. You can look up the +40c and +100c in the product data sheet PDS to input and compare them.
I'm too lazy to compare a 0w-20 weight, but it will indeed be thinner than a 0w-30 at ANY temp. I haven't cooked up a graph in a while, but there are surprises, like 5w-30 being thinner than 0w-40 any most temps.
The 0w-30 Castrol here is a thicker Euro one, the same visc as 0w-40 for our purposes. 5w-40 is 3-4x thicker than 5w-30 in cold! That's why 0w-40 were invented.
Light oils are for USDM to meet EPA MPG goals. If you drive like a granny in wintertime, they work fine. If you have your AMG on the track at +100F, no.
I'm going with some GF-6 SynPower 0w-20 I already have a case of 5q. 504 oil is a great option, but I recommend Pennzoil Euro L 5w-30 a similar mid-saps oil at a good price. Shell Rotella Truck is another great choice. Any oil with less than 1500ppm of calcium is ideal, basically GF-6 / Dexos 1.2 is applicable, and 30 weight is more ideal for us guys.
Those charts are a bit misleading by using the 2013 508 88 / 509 99 5w40 instead of the 2018 508 00 / 509 00 0w20. The 2013 specs are not DPF/GPF compatible at all. And the 508 88, whatever that is for, is not what B9 uses. B9 uses 508 00 0w20.
But there's nothing mysterious about Audi's move to 508 00 / 509 00. Totally about lower emissions (hand in hand with better mpg), they straight up say that themselves.
Interesting write up regarding 508 88 / 509 99. It's a 5w-40 alternative where 504/507 is not permitted (by VW), ie South America (read, Brazil) where fuel quality is poor. http://db.tecdoc-module.bg/files/201...7032402255.pdf
From the charts, seems high on sludge and deposit control, but lacks oxidative thickening (or seems more correctly stated, resistance to oxidative thickening). The glossary implies that's controlled by anti-oxidants. No idea why VAG would just leave that out of this specific oil.
I'd prefer to see exactly why Lubirzol rated each of the values for the oil specs. Some of them just seem beyond fringe.
I'm leaning towards Shell Rotella "GT" Gas Truck 5w-30. It's got all the desirable qualities, but just under 11cSt, it's "inbetween" a 20 weight and oils with 3.5cP HT/HS, it should be 2.9 minimum
Boron, Moly, Magnesium with reduced Ca. https://pqia.org/shell-rotella-gas-t...-20-motor-oil/
Dexos 1.2 is a good start.
I'm still considering Pennzoil Euro L 5w-30, but I don't need the higher HT/HS. It has MB 229.51 which is mid SAPS high HT/HS
Last edited by Audi Junkie; 07-24-2022 at 08:09 AM.
10-24-2019, 05:14 PM
