I learned something today...

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After draining my oil filter I took it inside and took a small pick and poked holes in the anti-drainback valve. After setting the filter back down I got some more oil out of the filter.
 
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I run a screw into one of the holes to push the antidrain back flap out of the way, then set the filter in a funnel with the screw the lowest part so it drains into a jug. Best pull filter when oil is good an hot as you get the most drained out that way.
 
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There seems to be some vacuum inside the dirty side of the canister that is just enough to prevent the oil from flowing back through the media. Break that vacuum and it'll drain easier. I poke a hole in the dome end of the can and set the filter up-side down in an old coffee can for a few days to drain them before cutting them open.
 
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Chevrofreak has the best method because he can get the hole absolutely the lowest point for complete drainage. Opening the antidrainback still leaves an edge where an ounce can be left behind. I would do the hole thing, but would need to use a drill because hammering it with a nail tends to dent the can and then it may not all drain out.
 
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I do the same thing as Chevorfreak, only I stand the filter in the funnel (dome down with hole poked in the center), it drains directly into the waste jug. I'll leave it for a day or so.
 
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 Originally Posted By: wannafbody
After draining my oil filter I took it inside and took a small pick and poked holes in the anti-drainback valve. After setting the filter back down I got some more oil out of the filter.
Just curious and trust me, I'm not trying to be a smartarse - was your expectation that the ADBV was non-functioning? Or a useless appendage? Or that all the oil came out on it's own - via the normal path? All filters I've ever drained - need assistance to get all the oil out. OH SHOOT I just remember my two filters are sitting outside in the rain. Carp
 

wannafbody

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I always assumed that the oil just drained out through the center tube. I had read that a filter won't completely drain and I wanted to check and see if that was really true.
 
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I can't quite figure the vacuum thing. I mean ..over enough time anyway. I can see the oil soaked (and perhaps somewhat plugged) media slowing air infiltration, but not preventing it. One would think that it would be harder for fluid to pass through the same saturated media and that just relieving any vacuum wouldn't do the job.
 
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 Originally Posted By: TallPaul
Chevrofreak has the best method because he can get the hole absolutely the lowest point for complete drainage. Opening the antidrainback still leaves an edge where an ounce can be left behind. I would do the hole thing, but would need to use a drill because hammering it with a nail tends to dent the can and then it may not all drain out.
I use a spring loaded center punch, and once it's through I pull the punch 90 degrees to pull the dent back out and open the hole up a bit.
 
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 Originally Posted By: wannafbody
I always assumed that the oil just drained out through the center tube. I had read that a filter won't completely drain and I wanted to check and see if that was really true.
Kind of reminds me of the "trick" used on oil filters that are mounted with the base down/top up (ie, RX-7s, 05+ Tacomas) to prevent a mess during an oil change. Punch a hole in the top of the filter and let the filter drain over night. When the filter is removed, there was zero oil mess ... whereas if you just drained the oil pan and then removed the filter 10 minutes later it would puke oil all over the place. In a case like that, the oil is trapped in the filter due to the anti-drain back valve and the vacuum factor. Put a straw in a glass of water, cover the end with your finger, remove the straw from the glass and you will see a column of water remains in the straw. Remove your finger from the end of the straw and the water falls out.
 
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