Do Subaru Factory Filters Anti Drainback Valves?

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Just changed the oil on my new Forester for the first time last weekend at 2700 miles. I warmed up the car for 10 minutes, cooled down for another 10 and pulled the drain plug, then filter - I hate figuring out plastic cover clips and stuck plugs and tight filters on the first changes.......

Anyway, the black Subaru filter that installs upside down was completely drained out. I cant see an anti drainback valve either. The Wix I installed has a valve. How can this be right from the factory?

I still need to cut it open and inspect. There was a little metal in the pan - some glitter in the light, but nothing alarming, but enough to justify in my mind an early change. My thoughts other than dry start ups - would the filter draining back regularly allow dirt to flow back to the pan? I know it is a small filter, but not good design. Anyone know if the blue subaru filters have valves?
 
If its mounted upside down I would think it should have a ADBV or it will have to refill the filter every start and that's not good. The old Subaru had a vertical mounted filter from below and didn't need a ADBV.
I this case I believe yes everything not hanging in the filter will go backwards at least as far as the pump.
 
I just looked under the hood of the loaner we had (2018 Forester) and seen that filter right there on top and upside down! It was black as well, not blue like the other OEM Subies I've seen.

My 08 Legacy has the filter on the bottom, very easy to get to and I guess it would stay full and not need a ADBV.
 
If that filter you took off had a part number ending in AA160, that's one that a lot of us wish we could buy in the US. I am presently using a Tokyo Roki filter intended for the WRX (not STI), I am comfortable with it since the engine in my FXT is almost identical.
Every Subaru/Tokyo Roki filter I've used has had an ADBV and they always have some oil in them when I take them off my car. I used one WIX/NAPA Gold filter with the higher bypass pressure Subaru seems to like and it just wouldn't stop weeping oil...I think the square cut seal on the thing had an overly prominent seam and oil still got out when I went gorilla on it. Went back to the Tokyo Rokis that I have never had issues with.
I used a couple of blue cans early on and didn't like that I could feel the case flexing when I tightened them, it just didn't sit right with me.
 
Have had 3 FB engines in the past 8 years.

Basic physics and fluid dynamics.

Doesn't matter if it has an anti-drainback valve- It will empty.

It is at the highest point on engine, above all oil galleries, NOT in a closed system. It will fill with air and drain.
Dry start every time.

Now how does that add you your BITIOG paranoia?
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Wife's last FB25 was burning oil at the rate of 1-2 per OCI at 55K miles.
No oil use, but excessive startup noise on the Crosstrek FB20.
 
Originally Posted By: cmlind
Just changed the oil on my new Forester for the first time last weekend ....
.... I cant see an anti drainback valve either ...

I still need to cut it open and inspect. ...


Its right there under the inlet holes. You may be thinking BYPASS which is in the can bottom on Roki's and Fram-arus. IN Wix its at the base end ( taking up all the filter space!)

If you want to emulate SUBARU OE replacement service parts you want to use a Fram Toughguard. That's basically what the dealer filter is.

Me ID look for a M1 filter in a large format. A low Bypass rating or 7-10 PSIG delta doesn't matter in the Non turbo engine in non "racy" environments.
 
Oil leaks out of the passages and bearing . The drain back valve is to keep the oil from back washing the filter. There are some filters with "double " anti drain back valves for certain applications.
 
If the filter ( with an ADBV) is low in the system (some are under the oil level) it will hold oil in the galleries and filter. at least overnight if the engine isn't put away wet.
 
If it it "upside down" no anti-drainback valve will prevent oil returning to the engine via pump clearances. May take awhile but the distortion of spacetime by the Earth(gravity) will empty the filter.
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Originally Posted By: Yah-Tah-Hey
If it it "upside down" no anti-drainback valve will prevent oil returning to the engine via pump clearances. May take awhile but the distortion of spacetime by the Earth(gravity) will empty the filter.
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It might empty the center tube and gallery down stream of the center tube depending on the configuration of the system after the filter mount. But the oil inside the filter and down to the pump would stay full if the ADBV seals 100%.
 
Originally Posted By: ZeeOSix
Originally Posted By: Yah-Tah-Hey
If it it "upside down" no anti-drainback valve will prevent oil returning to the engine via pump clearances. May take awhile but the distortion of spacetime by the Earth(gravity) will empty the filter.
smile.gif



It might empty the center tube and gallery down stream of the center tube depending on the configuration of the system after the filter mount. But the oil inside the filter and down to the pump would stay full if the ADBV seals 100%.


So oil wont go through the filter when its not under pressure?
 
Originally Posted By: Rand
Originally Posted By: ZeeOSix
Originally Posted By: Yah-Tah-Hey
If it it "upside down" no anti-drainback valve will prevent oil returning to the engine via pump clearances. May take awhile but the distortion of spacetime by the Earth(gravity) will empty the filter.
smile.gif


It might empty the center tube and gallery down stream of the center tube depending on the configuration of the system after the filter mount. But the oil inside the filter and down to the pump would stay full if the ADBV seals 100%.

So oil wont go through the filter when its not under pressure?


Oil should say in the filter between the media and the can if the ADBV is sealing 100%. The info below is from an old thread of mine, but the photos don't show anymore due to the "Photobucket Ransom". But as you can see below (and others have done this same test), the filter was full of oil after sitting base down for a week in a funnel. The oil only leaked out if the filter after I opened up the ADBV with some Q-Tips to hold it open.


---- From My Old Thread With Same Photos -----

Drainage setup for the filter to test the ADBV.
While the filter was still pretty hot I put it base side down in a funnel and let the hot oil drain out, and then left it to drain for a whole week. After the week of draining, I then jammed some folded over Q-tip sticks in 3 of the base plate holes to open up the ADBV to let the guts drain out in a clean glass bottle. What drained out was what the ADBV was holding back for a week.




Results of the oil trapped by the ADBV - it came out to 6 ounces.

A rough calculation of the volume between the center core and the can shell showed to be about 13.7 cu-in. Six ounces of fluid will take up 10.8 cu-in, so this means basically the ADBV was keeping the entire space between the can and center core full of oil indefinitely. Filter is in the cutter ready for dissection.

 
Here are the pictures. Yes it does have an anti drainback valve and still pliable. Didn't hold anything after 10 minutes. I understand it will drain down through the center tube, but thought there would at least be some left at the base holding the dirty oil from draining back to the sump. Filter quality looks very good. Damage is from removal and prying the element out of the can.




 
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So the factory Subaru filter does have an adbv, nitrile. Considering orientation, would have been surprised if it didn't. Imo, a silicone adbv would be preferable for this application. That said, Subaru should know that they are doing.

The only way to tell if it was holding oil on the dirty side is to basically replicate Z06 procedure. After letting it drain base down for a period of time, then hold open (qtip, nail or similar) one or more of the inlet holes and drain base down again, if adbv functioning more oil should drain out the inlet holes. I do it every time after removing a filter, before dissection. If no extra oil drains out then likely a compromised adbv. Oil left in center tube really tells you nothing.

After reading comment that no filter would hold oil in base end down orientation, remembering his thread wondered if Z06 would chime in. Point made. I'd add, 'some' similar filter applications include what's known as a standpipe to the center tube for added assurance. Seem mostly for big truck applications. There is a thread HERE about 'standpipe filters wiped out by photobucket scam. If interested I believe the same poster posted in another forum and the pics of the filters are still there.

http://www.toyota-4runner.org/maintenance-detailing/68152-larger-oil-filter-1gr-fe-4th-gen-v6.html
 
To sayjac intention I would say it depends where the filter is in the system. For this exercise, Just think of it as a check valve - forget all the other stuff for reasons of clarity. If ALL components are below oil ( or below mains drill) then it should stay filled regardless of orientation, and this has been my experience. The Subaru situation is different where its above everything engine and air will seek it was up then displace oil. You can tell they ( Subaru used FB filters) are empty as they are just a tad weightier than a virgin filter. I will say ive only change the oil after a overnight drain back or a 3+ hour cool down. I haven't changed the oil on the Crosstrek. Dealer only - they have a LIFETIME engine warranty - no mileage or time limit.++

- Trick Warranty? Yes! It doesn't cover "gradual" wear out and loss of compression - only sudden catastrophic failures. It is underwritten by and independent insurance firm sure to go out of business and change names every 2-3 years
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EXPERIMENT of the day to demostarte atmospheric air pressue. Fill a med juice glass 1/2 - 3/4 full put like a 3x3" piec of cardboard over the top, hold it on, invert glass and slowly remove hand. The "unattached cardboard should stay on the bottom of the glass preventing the water from spilling out.

Why? The glass is a closed system and the forces acting on the cardboard are but the mass (weight) of the water trying to push the cardboard off but instead counteracted by a (sea level) pressure of approx. 14 3/4 lbs per square inch. The effective air pressure on the covered mouth of the glass is over 19 1/2 pounds.

We sometimes forget we are living "under" a thin fluid not unlike a fish. Move your open hand back and forth quickly in front of you and feel is "viscosity"
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Our '14 and '15 Subarus came with Tokyo Roki AA160s, I would guess US-built Subarus come with blue cans.
I'd like to by this filter for my daughter's Impreza now that I have run out of Mazda-branded Tokyo Rokis that look just like it (examined them side by side) and have the same bypass pressure spec, but I guess it will end up getting blue cans as the AA170s I use appear to be too wide to fit into the cup in her car. Seems like people who try to buy the AA160 online end up getting the blue cans instead and the seller will just tell them that they are the same.
 
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