Originally Posted By: surfstar
1) You can't get all of the old oil out anyways (filter or no)
2) It has been proven that wear is higher with fresh oil following a change vs later in the OCI
3) Most filters hold 6oz or less if the sump is 5qts or smaller
4) New oil can have contaminants and that 'used' stuff in your filter may actually be cleaner, particulate-wise
5) It saves money, resources, landfill space, ...
6) Engines do not shed metals like they used to - filters do not 'get plugged' during normal OCIs
Actually surfstar is right, more or less, he just used so-so references. Some of the better references were contained within the references he made but someone would have to actually read thru the material to glean it... something people with closed minds usually don't take the trouble to do if the facts don't support their opinion. "Plausible deniability" I guess.
FIrst, RE: lower wear with old oil, I would point to a great study done by Ford and Conoco in 2007 which showed that aged oil, with more than 3000 miles on it actually showed less friction and wear than new oil and that the oil actually got better with age in this regard. You can read about it in SAE paper 2007-01-4133 "The Effect of Drain Interval on Valvetrain Friction and Wear." This was done in a collaboration between engineers at FoMoCo and Conoco (who designs and blends the Motorcraft oils). The paper is available at SAE.org (
HERE )
The abstract says:
"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."
Unfortunately, there are copyrights in effect on that paper, so if you want the full skinny, you have to pay to play, as many of us have done. It wouldn't be legal to post it. Dave Newton, dnewton3, has expounded on that study from a statistical standpoint and you can read more in the "What is Normal" stickies in the UOA section and we (the BITOG we) have discussed it at length if those who are interested wish to search. The 2007 study refers to an earlier one that found similar results while they were looking for something else.
As to new oil being dirty, it is. Not enough to be a problem but sometimes, initially, oil gets cleaner with use. If you do some google searches on new oil cleanliness, you can see it's a problem in some venues.. mainly bulk oils. My main point to make is to not assume new oil is some sterile, particle free liquid. Some oils are better than others, and there are some oils on the list I have that are very clean in comparison, showing the blender takes a lot of care. But particulate wise, your new oil may require some cleaning up from the engine oil filter and there could be a very short period right after the oil and filter is installed and the oil has made a few passes thru the fitler, when the oil is actually cleaner than when it was installed. Not that this really matters a hill-o-beans because, unless you are very unlucky and got some serious sludge-in-a-bottle, the "dirty" new oil is still within the safe operating threshold of the engine. But it does provide some interesting things to think about. One Noria source postulated that 17/14/13 is the optimal oil cleanliness level, but that is obviously only attainable with bypass filtration. In that regard, here is an interesting example:
A mining company went from very short 12,000 hour rebuild periods on their diesel equipment with oil running at 22/20/17 ISO codes to a predicted four-fold increase by filtering and maintaining the oil at a 17/15/13 level and the previous ISO code was achieved at 306 hours and the later was at 931 hours on the oil.
I was given access to some ISO cleanliness codes of new oil and I talked about it here
HERE but couldn't release data. I can release some of it now but not the lab that gave it to me. 2010FX4 and I collaborated on some tests to compare different methods of taking particle counts and our info is there as well. My Mac does not allow me to format this stuff in a way that works in these code boxes but it's readable. Take note that some of these are pore blockage tests and some are optical counter (OP)... and there is a significant difference in those test results, the pore showing lower, by about 25%) At one point in my list, the average oil cleanliness was 20/19/17 (all on the same optical particle counting machine).
That means in one ml of NEW oil, there are:
>4um= 5-10,000 particles
>6um= 2500-5000 particles
>14um= 640-1300 particles
Note also that some new oils on this list were as dirty as some used oil I have seen PC tested.
Here are some PC tests from my own truck. Note that the 5000 mile test is not that much dirtier than the Mopar 15W40 at 23/21/16, which was showing even more particle in the >6um range than the filtered used oil.
Virgin- 20/19/16 (MC 10W30 HDEO)
5000 Miles- 24/22/16 (before bypass installation)
9830 miles- 20/18/14 (4610 miles on 5 um bypass)
Code:
Date of test Oil Brand Oil Viscosity ISO4406 Test Type Virgin or Used Notes
6/3/09 Royal Purple 15W40 18/17/15 pore used/1682 mile pre LFS
10/20/09 Royal Purple 15W40 16/16/13 pore used 2251m post LFS
12/15/11 Motorcraft Super Duty 10W30 20/19/16 OP virgin container
12/15/11 Motorcraft Super Duty 15W40 20/19/18 OP virgin container
12/15/11 Motorcraft Super Duty 15W40 19/19/18 OP virgin container
12/15/11 Mobil Super 5000 5W30 20/19/17 OP virgin container
12/15/11 Shell Rotella T T6 5W40 20/19/16 OP virgin container
12/15/11 Chevron Delo 400 15W40 19/18/17 OP virgin container
12/15/11 Chevron Delo 400 15W40 19/18/17 OP virgin container
12/15/11 Chevron Delo 400 15W40 19/18/17 OP virgin container
12/15/11 Mopar MaxPro 15W40 22/20/15 OP virgin container
12/15/11 Mopar MaxPro 15W40 23/21/16 OP virgin container
12/15/11 Royal Purple Max ATF ATF 16/15/13 OP virgin container
3/21/12 Pennz Ultra SM 5W20 22/20/16 OP virgin container
3/21/12 Mobil Super 5000 SN 5W20 20/18/14 OP virgin container
