When I take my oil sample for analysis, I'd like to minimize the amount of oil I'm replacing so I get a better idea of how well the original oil's holding up over the entire interval. If I'm changing my oil filter at the same time (it'll be over a year on my car at that point), can I just dump the oil from the filter into the sample bottle? Any contaminants should be trapped on the anti-drainback side, right?
The other option would be to take a filler tube sample first, & then change my filter & dump the old filter's oil back into the engine. That's a lot more time & effort than the first option, & I'm not sure the readings will be any different. (Of course, if there's not enough oil in the center of the filter to fill a sample bottle 3/4 full, then I'm gonna hafta use a tube anyway.)
On one car, the filter's mounted vertically so I get a full filter of oil when I take it off. On the other car, the filter's mounted horizontally so I'd hafta crack it loose & catch what dribbles out.
Waddaya think?