Originally Posted By: demarpaint
Originally Posted By: y_p_w
Originally Posted By: demarpaint
Originally Posted By: y_p_w
I'd note that there's testing that indicates that metal wear is highest right after an oil change, and it levels out as the oil ages.
I read that study. I also read that fresh oil might be doing a lot of cleaning when its first added and could be the reason why metal wear is the highest right after an oil change. Some believe it is cleaning up what the "dirty" oil left behind. Both are interesting topics for sure.
I remember reading Usenet posts by Edward Kollin, who used to run Exxon's Advanced Fuels and Lubricants testing lab. He noted that wear tended to be higher in maybe the first 1000 miles after an oil change, and he attributed this to the required time for the ZDDP antiwear additives to heat activate.
Quote:
https://groups.google.com/d/msg/rec.autos.makers.saturn/matfrqy9psM/GbLFOkQZ9U4J
As for this discussion on oil change intervals, I have seen good oils
fail at 1500 miles and average oils run to 12,000 miles before failing.
It is certainly equipment and duty cycle related. I recommend 5-7k mile
oil change intervals for most people. If towing or high idle time this
can be reduced. One interesting point is that fresh oil will have a
higher wear rate until the ZDDP antiwear is activated(oxidized). The
wear rates of some 60-70 oils that I have tested improves over the first
1000 miles or so.
Edward B. Kollin
exxon Research and Engineering Advanced Fuels and Lubes Group
I read that too. After all the reading I did, and processing of information I decided in my applications I'd rather get that extra 15-20% +/- of oil out of the sump when I change the oil. The most compelling information to me was the slight spike in wear is the fresh oil doing some additional cleaning. Again how we process data, and our opinions vary.
All I'll say is that we've got a guy running the testing lab of a multibillion dollar petrochemical giant with access to all sorts of oil technology. He's not only testing his own company's products, but that of his competitors. I would think his lab would also be testing formulas that may or may not go into production and that they even adjust things like ZDDP, TBN, and detergent levels to see the effect of each contribution. That he attributed the wear to ramping up ZDDP activation tells me that it's not necessarily cleaning going on. It could very well be that reducing the level of activated antiwear additives means the ZDDP that bonds (to replace depleted molecules) to the surfaces is reduced or that the reduced concentration of activated antiwear additives in the oil washes it off the surfaces until it's saturated again.