Discussion about ADBV on a vertical oil filter

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I've heard competing views on this and thought this would be a good place to open some discussion on it. My Subaru and many others have vertical oil filters on it (threads are at the top....probably obvious) that are relatively low compared to the bottom of the oil pan (not lower than the pan though, but in that realm....as in it's not 2ft above the bottom of the pan). With this configuration, why would you need an ADBV. I know that the early OEM subaru filters (the white purolator made ones equal to 14460) did not have an ADBV. Is the gist, that while the car is off, you don't want the 'column' of clean oil post outlet of the filter, to drain down, flow the opposite direction through the media and back into the pan such that on next start up, it has to recreate this column of oil since the outlet passage is empty? And just to make sure I am visualizing things correctly, does the oil pump draw oil out of the pan, through the pump, into the dirty 'side' of the filter and then out of the clean 'side'....or is the pump on the clean side? I'm actually embarrassed to say that after 10 years of working on my car(s), I don't know the oil flow schematics of a car.
 

09rexwagon

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 Originally Posted By: Onmo'Eegusee
Filter is after pump. ADBVs do not work that well as to have a column of oil above it. Just keep the filter full for X hours or whatever.
So even without an ADBV, can oil slip past the lobes/vanes on the oil pump as it tries to flow back into the pan? I'd assume that with a healthy pump, it should not have gaps enough to let it reverse flow past the pump with the car off. So even with the best ADBV in a filter, if you leave the engine off for a week, chances are the oil will have slowly crept backwards and there will be empty oil passages at the next start to fill up?
 
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Oh, the pump will offer little resistance to oil back flowing. Very likely, yes, after a week you will have dry passages. The filter will be full, since it is vertical, but that is it.
 
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The HL has the same vertical filter. It's at the same level as the oil pan. If I have any balls the next oil change, I'll unscrew it before I drain the pan. My bet is with Onmo. There will be no column of oil even after just a few hours.
 

09rexwagon

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 Originally Posted By: bepperb
The HL has the same vertical filter. It's at the same level as the oil pan. If I have any balls the next oil change, I'll unscrew it before I drain the pan. My bet is with Onmo. There will be no column of oil even after just a few hours.
Yeah I see your point. However I usually do my OC right after the engine is running so there is always a column of oil when I remove the filter. Regardless, point is that this ADBV (and even further, the nitrile vs silicone) argument isn't really worth the effort because after letting your car sit overnight (very common occurrence, no?), chances are at cold start you'll have to repopulate the oil passages as the engine cranks?
 
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Yes, on these I guess. I still wonder of on a nitrile ADBV if in extreme cold the not-pliable nature of it reduces flow compared to silicone which is much more pliable at below freezing temperatures (or all the time). I do mine warm as well, but I'm willing to wait an extra few minutes for the sake of science.
 
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 Originally Posted By: bepperb
My bet is with Onmo. There will be no column of oil even after just a few hours.
That's right. I have a veritical, threaded end up, relatively low mounted filter, too. Oil mostly stays in the filter, (a little siphons out then stops) but overnight or a day or two at most, nothing will run from the center nipple on the engine when I pull the filter off. This vehicle is driven average twice a week. It is impossible to seal perfectly with a normal filter mount even if the ADBV is perfect. Oil can still slowly seep out between the threads of the center nipple and bypass the filter while seeping back to the pan. There is no O-ring or anything on that filter to nipple non-tapered thread. It will always seep backwards.
 
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 Originally Posted By: 09rexwagon
So it almost makes me doubt the point of an ADBV even on a horizontal filter. /Regardless, point is that this ADBV (and even further, the nitrile vs silicone) argument isn't really worth the effort because after letting your car sit overnight (very common occurrence, no?), chances are at cold start you'll have to repopulate the oil passages as the engine cranks?
The low mounting makes it more important. The ADBV is to slow the back washing effect ..not to 100% assure a full filter. It's a nice side effect for engines that evidence excessive noise at start up. Vertical mounts that don't use one probably (my reasoned speculation) don't have a substantial standing oil column upon shut down. As soon as the center well is exposed, all siphoning stops. Even some hydraulic filters have them for this reason.
 
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I think they help, but the filter will eventually drain until the level is below the center hole
 
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Most of the oil column backflows through the element. from the clean side to the dirty side, and then to the pan through the pump.
 
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Even with an old, hardened nitrile ADBV, when you shut the engine down warm, it will still be pliable enough to seal. Rubber is more flexible warm than cold. I have found used filters hold on to their oil for dear life. I have left filters upside down for a week or more and not had the oil drain out. Even in my foolish youth when I was using Frams. Better shops crush oil filters to remove the oil before disposing. No crusher, but I have a drill, and use it to make a drain hole in the dome end. I seldom have had start up noise with sideways filters, cheaper brands such as AC, Purolator, ST, and Fram, and using 5W-30 oil. Run 20W-50, and it is less likely to go anywhere.
 

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Ok, so let me see if I make a somewhat concise statement that most (if not all) of you can agree on: "With a vertical oil filter on an engine that is relatively low on the vehicle with respect to the sump, an anti drainback valve is somewhat non effectual from the standpoint of maintaining full oil passages in the engine while the engine is not running. After (let's say) 5 hours, it is likely that oil will drain back through the filter, through the pump and back into the sump (leaving only the filter full of oil. However, a quality ADBV would be beneficial from the standpoint of allowing the dirty oil to flow past the rubber/nitrile/silicone valve into the dirty 'side' of the filter with minimal impedance, even when the ADBV is cold." That sound about right?
 

09rexwagon

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 Originally Posted By: labman
Even with an old, hardened nitrile ADBV, when you shut the engine down warm, it will still be pliable enough to seal. Rubber is more flexible warm than cold. I have found used filters hold on to their oil for dear life. I have left filters upside down for a week or more and not had the oil drain out. Even in my foolish youth when I was using Frams. Better shops crush oil filters to remove the oil before disposing. No crusher, but I have a drill, and use it to make a drain hole in the dome end. I seldom have had start up noise with sideways filters, cheaper brands such as AC, Purolator, ST, and Fram, and using 5W-30 oil. Run 20W-50, and it is less likely to go anywhere.
You know that is a good point. I've taken oil filters that I let drain on my oil pan for hours and then soon as my dremel pierces the side of the can when I go to cut it open, a ton of oil then drains out of it. Now, if I know I will cut a filter open, I use a drill bit and drill holes through the ADBV through all the dirty side holds and let it drain like that for a few hours too.
 
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 Originally Posted By: 09rexwagon
Ok, so let me see if I make a somewhat concise statement that most (if not all) of you can agree on: "With a vertical oil filter on an engine that is relatively low on the vehicle with respect to the sump, an anti drainback valve is somewhat non effectual from the standpoint of maintaining full oil passages in the engine while the engine is not running. After (let's say) 5 hours, it is likely that oil will drain back through the filter, through the pump and back into the sump (leaving only the filter full of oil. However, a quality ADBV would be beneficial from the standpoint of allowing the dirty oil to flow past the rubber/nitrile/silicone valve into the dirty 'side' of the filter with minimal impedance, even when the ADBV is cold." That sound about right?
Not to me. As it cools, the ABDV will harden in place continuing to seal unless disturbed. If the ABDV leaks, the oil would flow into the outlet, through the media and out the dirty side to the pump and pan. Gee I wish I could remember more of my ''drain cold'' phase. My idea was that the longer the engine sets, the more oil drains down to the pan. Now, I tend to drain hot and let it set, maybe even overnight. If you had a thread end up filter, if you are correct, after setting overnight, you shouldn't get much oil to come out when you removed it. Note, drill the hole in the center of the dome end and stand it thread end up.
 
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Sound about right to me. But labman has a point about the seal setting as it cools. Still, eventually, some oil (the column) will drain through the threads. It won't empty the filter though because gravity will keep it in. If you have a good filter without high restriction it should pump that column back up very quickly. Interesting aside: The OC/47 Mahle filters I use on the VW have a spring loaded rubberized metal disc for both inlet and outlet. That should prevent any drainback at all. I would use them in other apps, but the bypass is too high for what is spec'ed for my truck or wife's car. Haven't found a compatable Mahle number yet.
 

09rexwagon

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 Originally Posted By: river_rat
Sound about right to me. But labman has a point about the seal setting as it cools. Still, eventually, some oil (the column) will drain through the threads. It won't empty the filter though because gravity will keep it in. If you have a good filter without high restriction it should pump that column back up very quickly. Interesting aside: The OC/47 Mahle filters I use on the VW have a spring loaded rubberized metal disc for both inlet and outlet. That should prevent any drainback at all. I would use them in other apps, but the bypass is too high for what is spec'ed for my truck or wife's car. Haven't found a compatable Mahle number yet.
Mahle are just filter cartridge style like in the Bimmers right?
 
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Sometimes I am a slow thinker. If the ABDV let the oil above the filter run out, it should let the oil above the lowest inlet hole out too. So if you let it set the mentioned 5 hours, you should be able to remove the sideways or thread down filters without oil going everywhere. Maybe in the interest of science, I will try that next oil change. After all, I think my truck has pockets that trap about 2 quarts when I drain it. How much harm can letting filter cool before removing it do?
 
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 Originally Posted By: 09rexwagon
Mahle are just filter cartridge style like in the Bimmers right?
No these are spin on. About 3" diameter and 4.75" long. Bypass setting is somewhere around 30 psi if I remember right.
 
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