Mobil1 SS 5w-30 and 0w-40, '02 Audi A4 1.8T

[Quattro Pete]

A handful of M1 oil analysis results on a relatively new Audi A4 1.8T engine, courtesy of another fellow AudiWorld member. Just a few clarifications:

(a) The oil sump capacity is only 3.7 quarts.
(b) Samples #1 and #4 are basically VOA samples.
(c) No oil consumption has been observed.
(d) The last batch of 0w-40 is still in the engine and will be drained and analyzed when it hits 10K miles.

As usual, all comments, good and bad, are very welcome.

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Equipment : 2002 Audi A4 1.8L turbo quattro

Oil filter : Audi OEM (Mann/Mahle)

Air filter : Audi OEM

Oil brand : Mobil 1 SuperSyn

Location : South Florida

Driving Type: approx. 60% hwy, 40% city

Lab : Herguth Laboratories

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Sample : #1 #2 #3 #4 #5

Oil type : 5w-30 5w-30 5w-30 0w-40 0w-40

Car miles : 10195 15089 20098 20164 25249

Miles on oil: 0 4894 9903 0 5085

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TBN: 10.79 4.55 3.3 10.42 5.64

Vis @100Deg C: 10.42 10.28 11.57 14.29 12.94

Oxidation :
Water FTIR :
Nitration :
Percnt Fuel :
Percnt Glycol:
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Metals

Iron :
Aluminum :
Chromium :
Copper :
Lead :
Tin :
Nickel :
Silver :
Silicon : 2 16 16
Sodium : 10 8 10 7 10

Boron : 188 103 105 224 128

Zinc : 903 914 868 878 792

Phosphorus : 824 736 744 900 770

Calcium : 2677 2727 2679 2860 2580

Magnesium : 17 53 52 20 25

Barium :
Molybdenum : 81 69 69 87 76

Vanadium :

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[ April 24, 2003, 10:20 AM: Message edited by: Quattro Pete ]

 

[segfault]

High silicon on the 5w30 run probably due to engine break-in. I believe that the engine was not fully broken in on the 5w30 run, and it would be misleading to conclude that there is less wear with the 0w40 without giving the 5w30 another try.

It's interesting that the TBN drops off quickly at the beginning of the run, but (judging by TBN) the oil soldiers on until the end of the 10,000 mile run without losing that much more TBN. I didn't realize that TBN loss was logarithmic.

The 0w40 has lost almost 10% of its original viscosity.

edit: Another comment: Based on the data so far, it appears that both oils protect the engine equally well.

[ April 24, 2003, 10:57 AM: Message edited by: segfault ]

 

[Patman]

The #3 run is interesting, it's viscosity is much thicker than typical for 5w30 SuperSyn, yet there is 3% fuel in there too. If anything I'd have expected this run to show the viscosity around 9.0 or less.

Does this engine typically have a history of such high iron content, or is this particular example higher than most?

[ April 24, 2003, 11:14 AM: Message edited by: Patman ]

 

[Quattro Pete]

My own 5K mile M1 SS 5w-30 UOA showed Iron content of 16 . The engine had 20K miles at that point.

Another 1.8T owner's 10K mile M1 SS 5w-30 UOA showed Iron content of 12 . The engine had 30K miles at that point.

So yeah, the Iron numbers in this thread seem a little bit elevated.

Also, we suspect the elevated Silicon level may have to do with the car being operated in south Florida, with all that sand and maybe an occasional trip to the beach.

 

[Jay]

This report seems to be a fairly good back-to-back comparison of 30-weight vs 40-weight in columns 2 and 5. The 40-weight doesn't appear to be reducing wear at all in this engine compared to the thin (almost 20-weight) 30-weight.

 

[Quattro Pete]

I have a question: what does Magnesium do in the oil? Is it an additive? And how did it get from 17 to 50+ in the 5w-30 samples?

 

[Patman]

Magnesium is an additive in the oil, used for cleaning purposes. TriSynthetic Mobil 1 used a lot of magnesium (way over 1000ppm) but SuperSyn uses very little (under 50ppm)

 

[buster]

#3 shows M1 thickening to a mid/high 30wt. Wear numbers are decent but doesn't it seem the TBN has dropped fairly quickly for the 0w-40? 0w-40 also thinned down quite a bit.

[ April 24, 2003, 05:25 PM: Message edited by: buster ]

 

[Al]

I have mostly the same feelings that the other posters express. My overall impression is that the 40 wt didn't do a whole lot better than the 30 wt. In other words-I'm disappointed in the 40 wt in this vehicle. I see no reason to continue with it (Just MHO) The lower silicon was probably die to the progressive drop in sealant/gasket contamination of a new car. I bet the 10W-30 would have done better than the 5W and maybe as good as the 40 wt.

 

[TooSlick]

QP,

For all practical purposes, the results in terms of wear protection and oil degradation with the 5w-30 and 0w-40 look the same. The #3 sample has thickened up slightly due to oxidation after 10,000 miles - no surprise there. The 0w-40 sample is showing some minor shearing @ 5000 miles - again no surprise. These two oils look to use an identical additive chemistry, so if the 0w-40 showed any advantage it would strictly be a viscosity effect. The fact that you don't see any with a turbo engine used in the Florida climate would indicate that there is no particular advantage to running a 40wt oil in this 1.8L turbo. My 2002 Audi TT recommends a 0w-30 as the primary grade and I can see where Audi and VW would be comfortable with this.

Wear rates seem a bit high in both cases, compared to other 1.8L engines I've seen. However, they are very consistent so I'd say they are normal for this particular engine run under these conditions. Chrome wear is low so I don't see any evidence of abnormal amounts of silicon being sucked into this engine.

TooSlick

 

[YZF150]

5000 would be my upper limit with this oil, in either grade. I wouldn't want to go below half on the original TBN. I wonder what the iron would be at, say 4000?

 

[Patman]

quote:

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Originally posted by TooSlick:
QP,

For all practical purposes, the results in terms of wear protection and oil degradation with the 5w-30 and 0w-40 look the same. The #3 sample has thickened up slightly due to oxidation after 10,000 miles - no surprise there.

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I am still surprised at the viscosity of that one, since there is 3% fuel in it too. Plus in the LS1 synthetic oil study he's at 8k on 5w30 SuperSyn and the viscosity is still close to it's original starting point.

 

[Eiron]

Well, I'm gonna take the opposite side of the "no improvement" & "no advantage" comments I'm seeing here.

First of all, if the 5W-30's already providing exceptional protection, why is "no improvement" even being considered? I mean, how much better are you expecting it to get on a relatively new turbo engine?

Secondly, if you had the choice between two oils for a turbo engine in a warm climate, at the same cost & convenience, and the same fuel efficiency, but one offered better HT/HS for improved bearing protection, why would you not pick the one with better HT/HS?

Is this an example of unrealistic expectations combined with viscophobia, or am I missing something here?

My only question:
What did your friend do to get 66mi on the car between draining the 5W-30 & adding the 0W-40? (A flush of some kind? Extreme torture testing?)

 

[TooSlick]

Greg,

Look at the data here for viscosity ....The 5w-30 is almost completely shear stable @ 5000 miles, while the 0w-40 has already thinned out by almost 10%. Given their relative HT/HS viscosities of 3.1 Cp and 3.6 Cp, I'd argue that both oils are roughly as thick after 5000 miles. The Mobil 1, 5-30 and 10w-30 are thinner to start out with, but are almost completely shear stable.
At this point I'd be inclined to run the Mobil 1, 10w-30 for a high performance application. It seems to hold up the best of all their SAE grades, with the possible exception of their 15w-50.

The only way to truly tell if the 0w-40 is providing significantly better results is to do something like this:

Run 5w-30/0w-40/5w-30/0w-40

See if you can get the wear rates to jump up and down by switching grades. I think for this particular motor, they'll come out about the same. I plan to run the Amsoil 10w-40 and some of their 30wt synthetics in my Audi TT. I'll let you know how the results come out, but at this point I'll be surprised if the 10w-40 provides significantly better wear protection.

TooSlick

 

[Jay]

quote:

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Originally posted by Greg Netzner:

...Secondly, if you had the choice between two oils for a turbo engine in a warm climate, at the same cost & convenience, and the same fuel efficiency, but one offered better HT/HS for improved bearing protection, why would you not pick the one with better HT/HS?...

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First, the lower viscosity oil will provide better gas mileage because of it's lower HTHS. Second, the higher HTHS didn't lower wear. So lets turn the question around--Why would you pick the oil with the same protection that gives poorer gas mileage?

 

[TooSlick]

Greg,

I would only add that the 0w-40 may show some benefits in other applications over the 5w-30. So I don't think you can generalize that it doesn't provide some added protection in different types of motors.

Normally engines that run under high loads and low speeds do better with thicker oils. Engines that run under light loads and high rpms do better with thinner oils, where rapid oil circulation is a major concern. Oil also has to properly cool the engine and flush away contaminents as they are generated. People tend to focus on wear protection to the exclusion of everything else.

TS

 

[buster]

quote:

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Second, the higher HTHS didn't lower wear.

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How does the HT/HS really effect wear though?

 

[Eiron]

Guys, guys, guys....

We're jumping to conclusions again!

TS,
Yes, in this application, the 5W-30 appears to be a bit more stable than the 0W-40; 1.5% thinning compared to 9.5%, or an 8% difference. But the 0W-40's still 26% thicker than the 5W-30, & that's nowhere near being the same. (I haven't seen anything directly relating viscosity values to HT/HS values.)

And you can't say that the 5W/10W-30s are "almost completely shear stable," because we don't have enough data for comparison! We have exactly three applications of M1SS 5W/10W-30 in turbo engines. We have Pete's 5W-30, a 10W-30 run for 4700 miles in a S-80 T6, & a 10W-30 run for 2200 miles in a Talon. The S-80 has unknown oil capacity, unknown makeup oil or filter changes, & unknown driving style (other than a few hi-speed runs), & it tested at 10.0. The Talon has unknown capacity, 1qt of makeup oil, & 70%hwy/30%city driving, & it still thinned out to 7.85! That's 20%, in 2200 miles, with 1qt of added makeup oil!!

I agree that you don't want something "too thick," but I just don't see it here. H*ll, last weekend I pulled off my oil filter full of 15W-50, in a 40*F garage, & the stuff poured as thin as vegetable oil!

Jay,
I'd say more folks are reporting mileage increases from switching to 0W-40, not decreases! This tells me the improved hydrodynamic film is providing more benefit than the imagined detriment created by increased viscosity. So, to hand you back your turn-around of my opposite viewpoint, "Why would you pick the oil with the same protection that gives poorer gas mileage?"

So again, is this a case of unrealistic expectations combined with viscophobia?

 

[segfault]

quote:

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Originally posted by Greg Netzner:
The S-80 has unknown oil capacity...

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I can answer that one for you. The "official" Volvo number is 8 quarts, but the guys on BrickBoard say that 6.5-7.5 quarts will bring it to the "full" mark.

 

[jason07-1zzfe]

quote:

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Originally posted by Greg Netzner:
...& a 10W-30 run for 2200 miles in a Talon. The S-80 has unknown oil capacity, unknown makeup oil or filter changes, & unknown driving style (other than a few hi-speed runs), & it tested at 10.0. The Talon has unknown capacity, 1qt of makeup oil, & 70%hwy/30%city driving, & it still thinned out to 7.85! That's 20%, in 2200 miles, with 1qt of added makeup oil!!...

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Fuel 1.8 %
Antifreeze = 0.15 %

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