Hot vs cold oil change video, long vs short drain time lapse.

[supton]

Perhaps around a 8:1 ratio, fresh to dirty?

Thing is... that 1/8th of the capacity that is "dirty"... just how dirty is dirty?

I mean, if you routinely run your oil into the chunky stage, then yeah, 8:1 doesn't sound all that good.

If you change the oil and it's however you want to think of it--half spent, 3/4 spent, something less than optimal--then it's more like 16:1, maybe 32:1, maybe better even.

And of course, even if you removed every drop of oil each time, giving the engine insides a hose down with brake cleaner, technically the last mile you drive for any given oil change, the oil is in the worst shape that it'll ever be in for that last mile--it's so bad and worn out, that's why you're changing it, right?



[For the record I usually walk away for 5 minutes or so, it's still dripping when I come back but I don't care, the oil wasn't "plumb wore out" and whatever's left would have been good enough for another 5k.]

 

[BHopkins]

Thing is... that 1/8th of the capacity that is "dirty"... just how dirty is dirty?

I mean, if you routinely run your oil into the chunky stage, then yeah, 8:1 doesn't sound all that good.

If you change the oil and it's however you want to think of it--half spent, 3/4 spent, something less than optimal--then it's more like 16:1, maybe 32:1, maybe better even.

And of course, even if you removed every drop of oil each time, giving the engine insides a hose down with brake cleaner, technically the last mile you drive for any given oil change, the oil is in the worst shape that it'll ever be in for that last mile--it's so bad and worn out, that's why you're changing it, right?



[For the record I usually walk away for 5 minutes or so, it's still dripping when I come back but I don't care, the oil wasn't "plumb wore out" and whatever's left would have been good enough for another 5k.]

Of course the guy that has to let the oil drip for the afternoon isn't the same kind of guy that would let oil go to the point of chunky, right? He probably isn't even the guy that lets the oil go all the way to Owner's Manual recommended oci. Maybe he is the 3k mile oci guy.

But the point is, when you still have something between 0..8 quart in a small 4 banger, to as much as 2 quarts still in a Ram Cummins, waiting for the last few drips makes very little difference.