Originally Posted by Patman
Here's the thing with this study that bothers me. That "aged oil" that supposedly shows lower engine wear, is also going to have contamination in it, especially direct injected applications that are dumping more fuel into it. So why would we want to leave our oil in longer when that's going on? Also, you can't possibly get every last drop of old oil out when you change it, there could be 10-15% of your total capacity left behind no matter how long you leave the drain plug off. I know with my Corvette, the manual says the capacity is 7 quarts, but when I refill it, the dipstick shows full with only 6 quarts added. So a lot is being left behind (I have seen pics of the oil pan and I believe a good half quart gets stuck in there alone) So my thought is that if the old oil helps "reactivate" the new oil, we don't really need to do anything different than we're already doing, as you'll always have that little bit of old oil doing it's job.
Has anyone even done testing of say, used oil & filter @ 25,000 miles (to satisfy your extended OCI cravings) and then simply swap in new oil and pull a sample after say, 10-15 mins of idle, then after 100 miles, 500 miles, 1,000 miles etc to see if wear does indeed increase simply with new oil being the only changed variable? This way the loaded oil filter remains the same to keep filtration identical.
I imagine if the fresh oil additives are indeed stripping the boundary layer, what makes us assume it's causing extra wear vs simply doing an initial clean up, and suspending particles that the old oil left behind, hence the increased "wear" in an analysis we see.
I've been doing 3,000 mile OCIs for years and I don't see any increased wear from all that fresh oil flowing thru the engine. In fact, I bet I don't even allow the oil to actually "age" with such short OCi's and thus, this "issue" isn't even an issue for me.
This brings up a question... how long does it take for an oil to age to perfection, like a good bottle of wine? 1,000 miles? 5,000 miles? 10? 20? When is it considered ripe and toasty? Seems like complete nonsense to me.
I always idle my hot engine after an OC to allow the new oil to flow thru the block nice and slow and "break-in" so to speak before I proceed to pound on it like I'm REALLY TRYING to shear it out of spec on purpose. LOL.
Here's the thing with this study that bothers me. That "aged oil" that supposedly shows lower engine wear, is also going to have contamination in it, especially direct injected applications that are dumping more fuel into it. So why would we want to leave our oil in longer when that's going on? Also, you can't possibly get every last drop of old oil out when you change it, there could be 10-15% of your total capacity left behind no matter how long you leave the drain plug off. I know with my Corvette, the manual says the capacity is 7 quarts, but when I refill it, the dipstick shows full with only 6 quarts added. So a lot is being left behind (I have seen pics of the oil pan and I believe a good half quart gets stuck in there alone) So my thought is that if the old oil helps "reactivate" the new oil, we don't really need to do anything different than we're already doing, as you'll always have that little bit of old oil doing it's job.
Has anyone even done testing of say, used oil & filter @ 25,000 miles (to satisfy your extended OCI cravings) and then simply swap in new oil and pull a sample after say, 10-15 mins of idle, then after 100 miles, 500 miles, 1,000 miles etc to see if wear does indeed increase simply with new oil being the only changed variable? This way the loaded oil filter remains the same to keep filtration identical.
I imagine if the fresh oil additives are indeed stripping the boundary layer, what makes us assume it's causing extra wear vs simply doing an initial clean up, and suspending particles that the old oil left behind, hence the increased "wear" in an analysis we see.
I've been doing 3,000 mile OCIs for years and I don't see any increased wear from all that fresh oil flowing thru the engine. In fact, I bet I don't even allow the oil to actually "age" with such short OCi's and thus, this "issue" isn't even an issue for me.
This brings up a question... how long does it take for an oil to age to perfection, like a good bottle of wine? 1,000 miles? 5,000 miles? 10? 20? When is it considered ripe and toasty? Seems like complete nonsense to me.
I always idle my hot engine after an OC to allow the new oil to flow thru the block nice and slow and "break-in" so to speak before I proceed to pound on it like I'm REALLY TRYING to shear it out of spec on purpose. LOL.
