Originally Posted by CR94
Originally Posted by ecotourist
The containers I buy hold a bit more than the sump in my Honda. I buy several containers (of the same brand) at once and for the first change pour out only as much as I need. I keep the excess in its original container. I use that left over bit first at the next change. The left over oil grows each time I change the oil, and eventually there's enough for a "free change".
That's exactly what I've been doing, except that I buy only one new 5-quart bottle between changes. I haven't yet reached my first "free change" in this car, accumulating leftovers at the rate of 5.0-4.4= 0.6 quarts per change. That should take 8 changes, because 70.6div>
I gain either 1.0 liter or 0.8 liters/change depending on whether I change the filter. It takes a while (I need 4 liters or 4.2 liters for a change) but the "free one" still feels pretty good.
The method I described above is really easy and avoids oil sitting in partial containers for long periods as well.
Only down side is you should use the same oil for multiple consecutive changes (about 5 in my case) to get a container of pure left overs, though I don't really think mixing oils matters very much.