Subaru Drainback Fix - Cheap & Easy*

Joined
Apr 4, 2010
Messages
650
Location
Washington State
The following is a cheap & easy(ish) solution for the annoying filter drain back found with some FB20 FA20 engines (top mnt filter). And that is to “simply“ use a filter with both an anti-siphon valve and anti-drainback valve. Although depending on where you live, finding one of these filters may take more effort than just 2 clicks on Amazon. But these filters can be had for less than 10 bucks, which is a lot less than the $260 Baxter charges for their anti-drain adapter. And they are direct fit with no mods. I’ll give background on how we came up with this Simple solution after I give some tips on How to find the Filters on the interwebs.

The easiest solution in the US Is to use a genuine OEM Kia filter 0FE3R14302 (google it). I got 3 on eBay for $15 delivered. I have no idea if these are NLA. But it has both valves and stopped the rattle on a friend’s ‘15 XT Forester. Of course, Most If not all the US will-Fit filters for this OEM PN probably do not have both valves (from what I can tell). However, for filters in Europe, it is not too difficult to find ones with valves. Filtron OP597 (NOT OP597/1 !!), Hengst H97w08, Mahle OC194, Mann W610/2 and W610/81, Sofima S3261R, UFI 23.2600.00. Tough to find in USA. The Filtron Link below has a very large interchange list. With applications, and many OEM Numbers (Mazda, Ford, Kia). The caution is all on this interchange list do not have valves. For example, list has both Fram PH4913 & PH5343. I think only 4913 has the valve and is NLA. List has Motorcraft FL821 which had the valve but is NLA, I think. On most the major Euro filter Mfg sites, the spec sheet will indicate if The PN has an anti-siphon valve explicitly, or with a cryptic specification of “R:2”. 2 means two anti-drain device. 1 means only one and you guessed it, 0 means none. I’ll show pics Illustrating in a reply to this post next post plus on how to physically ID (valve looks like an upper bypass but it’s not).

Interchange and filter specs.
Filtron OP597 specs link

A colleague of mine in Europe and I figured this out over beers awhile ago. He recently was relocated to Europe (Cummins engineer) and his family took two Subaru’s over (not a common sight on the Autobahn!). We had a work problem where Filters with a standpipe and one with anti-siphon were being tested. So we said, hey let’s find one for his subbies. We found a couple MANN&Hummels and installed. Cold start rattle went away Decent test as he and his wife only drove about once or twice a week so the cars sit quite awhile before start up. Whe I returned to US I found the Kia filter mentioned above.

Maybe this is not new info for anybody here amongst the filter geeks. Maybe somebody else knows a real Easy way to get a suitable anti-siphon filter in the US. I’m done looking into this as I don’t own a Subie. Just sharing a cheap and easy(ish) solution to an annoyance.

One thing we didn’t look into much was a filter with a standpipe. We check Donaldson, Fleetguard and Baldwin and saw none on M20 thread. Technically I prefer the standpipe due to its simplicity. Moving parts with the anti-siphon.

1F88226C-68D7-4DDB-B4D9-0AB48BF17D43.jpeg
C1C80A38-FABF-43D6-8802-D1653DCC85A8.jpeg
 
Last edited:

BBDartCA

Thread starter
Joined
Apr 4, 2010
Messages
650
Location
Washington State
Here are examples of how to identify filters in catalogs with two valves. R:2 = 2 anti-drain devices.
8516D1D2-B24A-4634-8230-22DD3B551F70.jpeg
 

Attachments

  • 4BA48C3A-2A93-4F42-891B-FD3CA09ADC6E.jpeg
    4BA48C3A-2A93-4F42-891B-FD3CA09ADC6E.jpeg
    64.2 KB · Views: 15

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,415
Location
PNW
What you see down the center tube might be the bypass valve. An anti-siphon valve might not allow any direct oil path between the center tube holes and the base plate center outlet hole depending on design. You'd probably have to cut one open to see if there's another valve (bypass) higher in the dome end.
 
Joined
Nov 1, 2011
Messages
598
Location
New Jersey
I keep spin the filter off while the drain plug is out.
Wipe the base clean with a rag.
Caveman EZ or am I missing something.
 

BBDartCA

Thread starter
Joined
Apr 4, 2010
Messages
650
Location
Washington State
What you see down the center tube might be the bypass valve. An anti-siphon valve might not allow any direct oil path between the center tube holes and the base plate center outlet hole depending on design. You'd probably have to cut one open to see if there's another valve (bypass) higher in the dome end.
You are incorrect. See these 3 pics, which shows lower bypass and upper check valve. I Started this post knowing the facts.
94C44873-1413-4D0A-B345-FA7F79243CFF.jpeg

09CBE615-46EF-4C92-8F16-945451FEE206.jpeg
48E763F8-BCF1-424A-8507-04CF8446AD90.jpeg
 

Attachments

  • DCB15344-FAF1-44CA-A7BC-41A9347EFFA4.jpeg
    DCB15344-FAF1-44CA-A7BC-41A9347EFFA4.jpeg
    81.8 KB · Views: 16
Joined
Feb 14, 2017
Messages
539
Location
iowa
really....take the filter off...wipe up oil around the base...put a new one on....done...what's the problem??
 
Joined
May 15, 2012
Messages
5,091
Location
The land of USA-made Subies!
Anti-siphon doesn’t matter. I spy with my little eye a nitrile ADBV, so your argument is moot. Besides, it’s apparent the filter assembly is too long; it was crushed during assembly showing poor manufactured quality.

Thanks for the discussion and pics, but hard pass.
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,415
Location
PNW
You are incorrect. See these 3 pics, which shows lower bypass and upper check valve. I Started this post knowing the facts.
Of course you know the whole story since you gave it cut open, but I was only going on the first set of photos, which was an incomplete story.
 

BBDartCA

Thread starter
Joined
Apr 4, 2010
Messages
650
Location
Washington State
Anti-siphon doesn’t matter. I spy with my little eye a nitrile ADBV, so your argument is moot. Besides, it’s apparent the filter assembly is too long; it was crushed during assembly showing poor manufactured quality.

Thanks for the discussion and pics, but hard pass.
The ADVB is not “nitrile.” Best we can tell it’s a FKM (Viton) series of material. I’d prefer silicone or not owning a Subaru.
 
Joined
Feb 3, 2020
Messages
875
Location
Los Angeles
I don't understand what the issue is. If ADBV is functioning correctly, there should be oil primed in the filter ready to pass through the filter and the then the center tube. What you're saying is the anti siphon valve on the inside of the filter holds oil inside the filter preventing the gravity drain back down the center tube. In theory, it could help but these filters are so small compared to your oil pumps volume. I think the problem you're having is related to the ADBV, and you should try a different filter with silicone ADBV. The problem sounds like the ADBV isn't working, and the oil has to travel much further.
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,415
Location
PNW
What you're saying is the anti siphon valve on the inside of the filter holds oil inside the filter preventing the gravity drain back down the center tube. In theory, it could help but these filters are so small compared to your oil pumps volume.
Some engines might allow the oil to drain back through the center tube and drain out some oil galleries in the engine. When oil drains back through an oil filter (either through the center tube, or through the base plate), it is also draining oil out of portions of the oiling system, not just out of the filter. The filter could still be full of oil, but there could be air in some places in the oiling system if oil drains past the oil filter.
 
Joined
May 15, 2012
Messages
5,091
Location
The land of USA-made Subies!
Zee, understood in theory… but with the oil that is always kept between surfaces because of “stiction” is there really any way to quantify or measure this? Or is it simply an inconvenience? One thinks that if this were a “measurable wear issue” that the mfr would require something like an anti-siphon valve, and require it as a warranty point. I mean, I get the logic, but where’s the data that shows these inverted filters without the anti-siphon valve experience more wear? One would think if this was an issue, the FA/FB engines would have been one of the first to show the results in increased engines that failed; and that does not seem to be the case.
 

ZeeOSix

$100 site donor 2022
Joined
Jul 22, 2010
Messages
34,415
Location
PNW
Zee, understood in theory… but with the oil that is always kept between surfaces because of “stiction” is there really any way to quantify or measure this? Or is it simply an inconvenience? One thinks that if this were a “measurable wear issue” that the mfr would require something like an anti-siphon valve, and require it as a warranty point. I mean, I get the logic, but where’s the data that shows these inverted filters without the anti-siphon valve experience more wear? One would think if this was an issue, the FA/FB engines would have been one of the first to show the results in increased engines that failed; and that does not seem to be the case.
There are a lot of engines with vertical, base down mounted oil filters ... I have one myself, a Toyota Tacoma 4.0L V6. Most don't require an anti-siphon check valve in the oil filter (none in my Tacoma filters). I know my Tacoma doesn't drain the oil filter, even if it sits for many day. When I do an oil change, I have to punch a small hole in the dome end to make the filter drain out the center tube. Apparently, there's enough surface tension in the oil to keep it between the center tube and can, and there is a slight vacuum effect working, like putting your finger over the end of a straw when it's filled with water, then removing it and the water says in the straw. I've seen this too when testing the ADBV way back on a PureOne when I let it sit base down for a week (LINIK). Punching a hole in the dome end allows ATM pressure to act on the oil inside the can between the center tube and shell.

And of course, there is always an oil film left on all engine parts after the engine is shutdown. But it would always be better to keep all oil in the oiling system after the engine is shutdown vs not. The engines that specify a filter with an anti-siphon valve must do some major oiling system drain-out after shutdown for them to specify a filter with an anti-siphon valve.
 
Joined
Jul 11, 2014
Messages
2,990
Location
Paradise of Florida


Or, you can make your own standpipe to use any common quality filter.

I guess the issue is that too many go to 'their guy/hack indie' or a quicklube and get the jobber filters that have pathetic ADBV performance.

I don't see the Subaru needing a standpipe. I do see it needed a quality filter with a functioning ADBV and some quality oil.
 
Joined
Sep 26, 2022
Messages
7
Location
Fort Collins, CO
I keep spin the filter off while the drain plug is out.
Wipe the base clean with a rag.
Caveman EZ or am I missing something.
The problem he’s talking about is oil draining out of the filter when the engine is off and there not being sufficient oil in the filter at startup, not it spilling when the filter is removed
 
Top