Porsche 996 - Oxidization? Joe Gibs DT40

[strathconaman]

So...two years of UOAs. The first on Fuchs GT1 5w40, the second on Joe Gibbs DT40

Code
OIL 5w40 5w40

Fuchs DT40

MILES IN USE 3.5k 4.6k

MILES 83k 87K

SAMPLE TAKEN 10/25/17 10/28/18



ALUMINUM 2.8 3

CHROMIUM 2.1 2

IRON 12 8

COPPER 5.5 6

LEAD 1.3 1

TIN 1.2 1

MOLYBDENUM 2.6 398

NICKEL 0.2 0

MANGANESE 0 0

SILVER 0 0

TITANIUM 0 0

POTASSIUM 2.2 10

BORON 49 92

SILICON 3.8 16

SODIUM 1.5 24

CALCIUM 1800 1679

MAGNESIUM 16 6

PHOSPHORUS 705 893

ZINC 868 1051

BARIUM 0 1



FUEL


WATER
VIS 210F 12.6 12.9

BASE NUMBER NR 3.6

OXIDATION 39% 30 abs/cm


The first lab did not report on Base Number, and reported Oxidation as a percentage. The second lab gave a base number of 3.6, and Oxidation of 30 abs/cm, whatever that is.

I have seen VOAs for DT40, but they didn't include oxidation, and I understand you need to understand the start number of the oxidation to understand the number after usage.

Can anyone tell me more about my oxidation numbers or know the start numbers for DT40?

 

[oil_film_movies]

DT40 is a PAO/POE oil, and its oxidation number probably starts high for new oil. That can be tricky.
Gibbs (Lubrizol really) changed the formula from just a couple of years ago:
https://www.bobistheoilguy.com/forums/ubbthreads.php/topics/4093325/VOA_Joe_Gibbs_DRIVEN_DT40_5W40
Lots of moly now, less Ca. Gibbs was reporting 13 cst KV100, and you've got about 12.8 KV100 (yours was done at 210F); therefore, there was a small amount of oxidation to counter fuel thinning.
I would stick to your schedule, once a year with that many miles is fine, and DT40 with all that moly has my vote for an oil to use here.

 

[zeng]

If this DT40 is made of PAO/POE, I wouldn't be concerned with oxidation numbers up to say, 80 or 90 as was the case with some Amsoil/RedLine products.
Very good metal wear rates.
At residual TBN of 3.6, there is still a lot of oil life left , IMHO.

 

[oil_film_movies]

Originally Posted by zeng
If this DT40 is made of PAO/POE, I wouldn't be concerned with oxidation numbers up to say, 80 or 90 as was the case with some Amsoil/RedLine products.

Gibbs says its PAO+POE, so, yes, we can believe that. They don't say what percentage POE is in it though. ... To be a high-temperature oil like Redline, it might have a decent % POE.

 

[dave1251]

The oxidation level in this sample is not concerning. At 7.5K I would resample.

 

[strathconaman]

Thanks for the info. I guess I will see what the numbers are like next year.

 

[strathconaman]

Due to a lack of planning on my part, I missed last year. Here are the 2020 numbers:

 Fuchs DT40 DT40
MILES IN USE 3.5k 4.6k 3.8K
MILES 83k 87K 94K
SAMPLE TAKEN 10/25/17 10/28/18 11/21/20
ALUMINUM 2.8 3 0
CHROMIUM 2.1 2 1
IRON 12 8 4
COPPER 5.5 6 4
LEAD 1.3 1 0
TIN 1.2 1 1
MOLYBDENUM 2.6 398 526
NICKEL 0.2 0 5
MANGANESE 0 0 0
SILVER 0 0 0
TITANIUM 0 0 1
POTASSIUM 2.2 3 0 
BORON 49 92 117
SILICON 3.8 16 12
SODIUM 1.5 4 4
CALCIUM 1800 1679 1812
MAGNESIUM 16 6 9
PHOSPHORUS 705 893 1060
ZINC 868 1051 1194
BARIUM 0 1 2
FUEL  WATER  VIS 210F 12.6 12.9 14.0
BASE NUMBER NR 3.6 3.79
OXIDATION 39% 30 abs/cm 33

The lab has flagged the nickel, but like the titanium in this sample, I can't figure out where it would be coming from. This is from an M96 engine in a 2002 911.

 

[RDY4WAR]

Random and odd numbers in unfamiliar elements isn't uncommon with ICP. The amount of an element is found by focusing on the specific wavelength for an element which generates peaks, except there's not always hard cutoffs between elements. If nickel is right next to molybdenum in the spectrum (not sure if it is, just using an example), some of the moly may crossover into the nickel spectrum and get read as nickel.

 

[Kboggs]

Thanks for the updated information. I switched to DT40 last year, and seems over the years it has improved with more moly and zddp than prior samples I have seen. I will have to post mine up soon and may also do an updated VOA.

 

[strathconaman]

2021 Numbers:

Fuchs DT40 DT40 DT40 MILES IN USE 3.5k 4.6k 3.8K 3.4K MILES 83k 87K 94K 97K SAMPLE TAKEN 10/25/17 10/28/18 11/21/20 11/14/21 ALUMINUM 2.8 3 0 2 CHROMIUM 2.1 2 1 1 IRON 12 8 4 4 COPPER 5.5 6 4 4 LEAD 1.3 1 0 1 TIN 1.2 1 1 0 MOLYBDENUM 2.6 398 526 482 NICKEL 0.2 0 5 0 MANGANESE 0 0 0 0 SILVER 0 0 0 0 TITANIUM 0 0 1 1 POTASSIUM 2.2 3 0 0 BORON 49 92 117 114 SILICON 3.8 16 12 11 SODIUM 1.5 4 4 6 CALCIUM 1800 1679 1812 1744 MAGNESIUM 16 6 9 10 PHOSPHORUS 705 893 1060 1063 ZINC 868 1051 1194 1125 BARIUM 0 1 2 1 FUEL WATER VIS 210F 12.6 12.9 14.0 13.9 BASE NUMBER NR 3.6 3.79 4.67 OXIDATION 39% 30 abs/cm 33 35