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I've attached the Oil Report with the first oil change of my 2010 Golf TDI I bought in August 2010. I mentioned in a prior post that I did an oil analysis on my 2010 MB ML 350 4Matic with the first oil change at about 5,000 miles rather than the recommended 10,000 miles. My plan is to increase the driving distance between oil and filter changes as much as possible based on the oil analysis reports. The first report on the MB revealed very high metal ratings, and the analyzer was surprised at the recommended 10,000 mile oil change interval. So I did an oil analysis of my TDI with a change in oil and filter at 2,963 miles after a little over seven months driving. Changing the oil and filter in the Golf TDI, as well as the MB ML 350, is easy with the top side oil filters (on both cars) and the DIY instructions. Anyway, here is the oil report for the Golf TDI. Robert
 

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The wear rates (ppm/miles driven) will be higher than normal during the first few thousand miles. But the rate will ease off and decrease after the first few thousand miles to "normal" wear rates. So, the total ppm at 10k miles will likely not be that much more than you are now seeing. There is really no need to change the oil at 3k miles.

Changing the oil too frequently, will likely cause higher wear rates than keeping the old oil in the car for the recommended OCI. Read this and draw your own conclusions. IMHO, since the TBN number is good, there's really no need to change the oil before 10k miles.
 

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There is really no need to change the oil at 3k miles. IMHO, since the TBN number is good, there's really no need to change the oil before 10k miles.

I'm sure that is true.

Changing the oil too frequently, will likely cause higher wear rates than keeping the old oil in the car for the recommended OCI.
I'm not sure about this, even after reading the link, although I know it is the subject of a long-running debate. I'll keep an open mind on it as I study it. Certainly if it does more harm than good to change it more frequently it would be better not to change it more frequently.
 

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I've never heard a good explanation for what the metals values actually mean, in terms of effect on engine components. What I mean is, what effect do 119 PPM of aluminum have on the engine or the oil? What if it was only 5? What if it was 10000? Obviously higher numbers indicate more of the metal winds up in the oil, but what does that say about the oil's protection characteristics? The oil is still lubricating and cooling, right? As long as the required additive levels are still good, the metals numbers don't really mean anything about the oil's lifetime, do they? Sorry if these are redundant questions. I really don't have time to sift through all the crap over at Bob is the Oil Guy.
 

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Absolutely, the oil is still lubricating very well at a 119 PPM and likely better than new oil. The metals and soot are suspended in the oil. I've read many including this analysis / study on Bob's and elsewhere. They all basically say the same as my link above. Here's one from Bob's. and another
The Effect of Oil Drain Interval on Valvetrain Friction and Wear

Date Published: 2007-10-29Paper Number: 2007-01-4133
DOI: 10.4271/2007-01-4133



Author(s):

A. K. Gangopadhyay - Ford Motor Co.
R. O. Carter - Ford Motor Co.
D. Uy - Ford Motor Co.
S. J. Simko - Ford Motor Co.
M. Riley - Ford Motor Co.
C. B. Phillips - ConocoPhillips Co.
H. Gao - ConocoPhillips Co.

Abstract

Engine oils are subjected to a series of industry standard engine dynamometer tests to measure their wear protection capability, sludge and varnish formation tendencies, and fuel efficiency among several other performance attributes before they are approved for use in customer engines. However, these performance attributes are measured at the end of tests and therefore, do not provide any information on how the properties have changed during the tests. In one of our previous studies it was observed that engine oil samples collected from fleet vehicles after 12,000 mile drain interval showed 10-15 % lower friction and more importantly, an order of magnitude lower wear rate than those of fresh oils. It was also observed that the composition of the tribochemical films formed was quite different on the surface tested with the drain oils from those formed with fresh oils. The objective of this investigation is to demonstrate how the friction and wear performance changed with oil drain intervals. A fleet of three vehicles was run in Las Vegas and oil samples were collected at various drain intervals from 3000 miles to 15000 miles. As in the previous study, the results showed that the aged engine oils provide lower friction and much improved wear protection capability. These improvements were observed as early as the 3000 mile drain interval and continued to the 15000 mile drain interval. The composition of tribochemical films formed on the surface with the 3000 mile drain interval is similar to that formed with the 12000 mile drain interval as seen before. These findings could be an enabler for achieving longer drain interval although several other factors must to be considered.




Raman Characterization of Anti-Wear Films Formed from Fresh and Aged Engine Oils

Date Published: 2006-04-03Paper Number: 2006-01-1099
DOI: 10.4271/2006-01-1099



Author(s):

Dairene Uy - Ford Motor Co.
Steven J. Simko - Ford Motor Co.
Ann E. O'Neill - Ford Motor Co.
Ronald K. Jensen - Ford Motor Co.
Arup K. Gangopadhyay - Ford Motor Co.
Roscoe O. Carter - Ford Motor Co.

View All CollapseAbstract

Engine oils contain additives that provide wear protection to prolong engine life. In a previous study using direct acting mechanical bucket valve train components, we found that aged oil provided better wear protection and friction reduction under certain circumstances. To understand this effect further, friction and wear performance of fresh and laboratory-aged oils with 0.1% phosphorus was studied with ball-on-flat and cylinder-on-flat rigs. Test durations were chosen according to the electrical contact resistance (ECR) values observed between the contacting surfaces.

Anti-wear films were characterized primarily by UV and visible Raman spectroscopy, and results were corroborated by Auger electron and infrared spectroscopies. The greatest compositional differences occurred between films formed by fresh and aged oils. The degree of ECR response or the length of oil aging generally did not affect the type of component observed in the films. In films formed by fresh oil, FeS 2 , orthophosphates, and carbonates were present, while another type of phosphate and little or no carbonate were present in the films formed with aged oil. Additional components detected in both films were Fe 3 O 4 , amorphous hard carbon, and a trace of hydrocarbon.

The combination of UV and visible Raman spectroscopy enabled the detection of various components at different depths in the anti-wear films. Lastly, the films can be heterogeneous when viewed microscopically, as revealed by the relative Raman intensities of various components sampled at different locations across the films.
 

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You guys wouldn't happen to be engineers now would you? :D
I only spent the first 7 years of my career in actual engineering. Just trying to educate people on the likely issues with too frequent oil changes with really no benefit.:D Plus, they'll save $$$ following the manufacturer's OCI. But to each his own.

Studies like the ones quoted are the reason auto manufacturer's have recommended longer OCI in recent years. Even their recommended OCI can likely be extended. IHMO, there's no benefit in doing early UOA or UOAs at all unless one plans to extend their OCI because one will likely always get elevated readings in the first few thousand miles (even more during break-in) until the wear rate lessens as the oil ages and becomes more lubricous. From many UOAs posted on tdiclub, VWoA OCI seems conservative.

As an aside, I started doing extended OCI in the late '70s with my 240D and then with my 300SD (long before UOAs became trendy). At that time the OCI was 3k miles. I began using Mobil Delvac 1 in about '79 and changed oil at about 10k intervals. Both engines had over 250k miles on them when I sold the cars with no issues, compression well within spec, and my mpg virtually the same then as when newer.
 

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Awesome information. The other component to the recommendation that oil should be changed more frequently is pure greed. They want to sell more product, whether that product is the actual oil or the service of changing the oil. I've always stuck to the manufacturer's recommended change cycles and lubricants and have had good results. From your experiences and research it seems one could go longer if they used the right oil.
 

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Discussion Starter #9
Obviously higher numbers indicate more of the metal winds up in the oil, but what does that say about the oil's protection characteristics?
At some point, wear accumulations and insolubles build up to a level that causes the oil to become abrasive. See the case studies at the following Blackstone web site for an explanation:

http://www.blackstone-labs.com/do-i-need-a-tbn.php

I think the debate is what is the optimal interval to change oil, and I think the answer is it depends on a lot of factors. I come from an aviation background, and if the engine quits running on a car it's generally not a big deal--you just pull over and call someone to come get you. You don't have that luxury in an airplane because there is no pulling over and just parking. For that reason, oil analysis in airplane engines is considered very important. You have to decide what's important to you.
 

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Thanks for the thoughtful replies. That's basically what I figured. I was already done with the 99.5% useless crap on the bob site. You've confirmed what I suspected.
 
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