Mobil 1 0w-40 HT/HS
- Thread starter buster
- Start date
- Status
- Joined
- Jun 2, 2003
- Messages
- 23,591
If the listed HT/HS refers to new oil, then how do we know an oil won't shear below what's required to meet the car maker's requirements? Seems scary, no?
- Joined
- Jun 2, 2003
- Messages
- 23,591
And how does HT/HS change with age of the oil?
- Joined
- Jun 2, 2003
- Messages
- 23,591
Just great.
Patman
Staff member
I'm just guessing, but I'd be willing to bet that when M1 0w40 shears down to 12cst, it's HTHS will go from 3.6 to about 3.3 or 3.4. What I'm curious about is if the HTHS will then go back up again as the oil thickens up later?
- Joined
- Jun 2, 2003
- Messages
- 23,591
Doesn't sound good to me. Why do I even pick an oil that meets the required HT/HS of 3.5 (in my case), if the HT/HS isn't stable? I tell you, M1 15W-50 looks more and more promising! I doubt that oil would thin out below an HT/HS of 3.5 (Unscientific guess!). I mean, the 15W-50 starts out with HT/HS 5.11.
Delvac 1, M1 10w-30, and 15w-50 are about as shear stable as you will find. I think any 0w-40 will shear a bit. It's just too much of a spread. Delvac 1 is a great oil, but hard to find. I am taking a look at the other Delvac oils now. Are any of the others good for cars? 1300?
moribundman, I don't understand why you are latching onto HTHS. I'm sure all oil test parameters change with usage. No parameter is guaranteed to be stable with usage.
Well it's only promising if your engine requires it or performs "better" with it. More is not necessarily better.
As most of you know, who have seen all I have written about German Castrol, I am enamored with it and so have no particular axe to grind for M1. However, as I read the comments made about M1 0W-40 all across this board, I can't help but wonder what is going on in people's minds with reference to this oil. It appears to me that what a lot of people are saying is either: (1) we think "our science," i.e. the analysis of the empirical data from UOAs is better than Mobil's, Porsche's, and AMG's "science" because we believe our data more than we believe their recommendations and confidence OR (2) we flat don't trust Mobil, Porsche and AMG and figure the relationships are based purely or mostly on financial arrangements rather than on research and testing. It seems to be a matter of trust. Here we have a major lubrication leader and two high performance auto manufacturers who believe in the stuff and we say, "I don't trust it." Maybe those of our group who are saying that are dead right, but I'll go with Mobil, Porsche and AMG. I trust their the fidelity and technical mastery of their engineering, research and testing. For those of you who would say, well this great Mobil you have so much confidence in has changed their formula 4 times in the short term. Isn't that noteworthy that they recognized deficiencies and--in today's litigation-happy society--without even being sued, took on the responsibility to do so?
- Joined
- Jun 2, 2003
- Messages
- 23,591
I'm latching onto the HT/HS, because that seems to be one of the more important points regarding an oil, at least if you work an engine hard. If I seem obesessed (and obnoxious), rest assured, it's just to beat some more information out of the dead horse, so to speak.
I still don't know why while, for example, VW says an oil has to have an HT/HS of at least 3.5 to meet some of their oil specs, it wouldn't matter if that oil actually shears down below the required minimum. Do they just assume an oil that has an HT/HS of 3.5 won't shear down far enough to cause a problem? Can anybody answer that question?
I'm pretty confident that M1 0W-40 is fine in my engine, but I question if it's the best I can get for the price. Sure, Redline sounds good, but the UOAs looked mixed, not to mention I prefer an off the shelf oil that I can easily get. And I'm not willing to pay more than 7 bucks for a quart. That's why I keep looking at M1 15W-50, which, for some reason unknown to me, seems to be shunned by many people here, while it seem to be one of the popular oils with people who have the older 2.8 Audi engine.
PS: I didn't mean to turn this thread into another thread about MY engine, but that's all I can really speak about. Thank your for your patience.
Does anyone know how the two methods compare in the results they produce? Any idea what redline would come out as under D4683?
Thanks,
Cary
moribundman, you're not obnoxious!quote:
Originally posted by moribundman:
I'm latching onto the HT/HS, because that seems to be one of the more important points regarding an oil, at least if you work an engine hard. If I seem obesessed (and obnoxious), rest assured, it's just to beat some more information out of the dead horse, so to speak.
In regard to the importance of HTHS, I will say that it is important that it's at least 3.5 for some or most EU engines. Keep in mind that HTHS limits for ACEA A2 'general purpose oil', A3 'high-performance extended drain oil', and Audi/VW 500/502 oil are all the same.
Why does VW/Audi specify 5W-40 in one engine and 0W-30 in another? Because that is what is required. Do these oils guarantee to have the same 40C and 100C viscosity after 7500 miles as they did when new? No. Does this mean we should use a different weight because of this? No. Does the manufacturer just assume an oil that has an HT/HS of 3.5 won't shear down far enough to cause a problem? Yes, as long as you follow the recommended oil spec (A3, SL, 502.00, 229.1), and the recommended normal or severe service interval. If you do not trust the auto or oil manufacturer, use UOA.
IMO, I would look at your UOA, not other's. Also, I would use an oil that meets the manufacturer's approvals (VW 502/500/501 for your engine). If you don't, in EU, they will not honor your warranty in oil-related claims. They are more serious about oil there.
M1 15W-50 is the preferred M1 oil weight for [our] 2.8 12V engine. Every VW/Audi mechanic I know agrees with this, because the 2.8 12V has relatively loose cold and/or hot tolerances, large passages, and burns some oil through it's low-tension rings and it's crankcase breather system. Thicker, less volatile oil is good here. Some 12v's have valve clatter at cold startup because of the design of the oil non-return valves under the valley pan, and the pressure relief valves under the valve covers. Some engines are cured with M1 15W-50 and others with 0W-40, depending on individual engine ideosyncrasies, season, etc.
I like M1 15W-50, Pentosynth 5W-40, and LM 5W-40 for my 2.8 12v. M1 0W-40 solved the valve clatter issue, but my engine guzzled it.
[ July 29, 2003, 02:54 AM: Message edited by: geo ]
- Joined
- Jun 2, 2003
- Messages
- 23,591
Oh, this is what I've been waiting for! Finally, someone here on this board (We both know what they say on the 12v forum about that issue) is in favor of M1 15W-50 for that engine. And you say the 2.8 12 v has loose tolerances (large clearances) and low-tension rings?
Anyway, the car does run fine with 0W-40. I get no valve clatter (Didn't get it with Syntec 5W-50 either), and oil consumption is about a 3/4 quart for every 10k miles (It was less with Syntec 5W-50).
I'll give Pentosynth 5W-40, LM 5W-40, or M1 15W-50 a shot next time.
Thanks for taking the time, geo.
[ July 29, 2003, 02:56 AM: Message edited by: moribundman ]
- Status
