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Fumoto F108SX is the correct valve for the 2.4 turbo and any F108 variant for the 2.5

45K views 186 replies 48 participants last post by  mnussbau 
#1 · (Edited)
TLDR: For the 2.4 Turbo the F108SX is the one to use, for the 2.5 any of the F108 series can be used including F108SX, F108N, F108, etc. Fumoto specifies 18 foot pounds to torque their brass valves, stock steel plug is 33 foot pounds. I've installed many Fumoto valves without using a torque wrench and they've never leaked. Do not use a crush washer with a Fumoto - they supply a felt washer with some, and the F108SX has an o-ring - do not add extra washers.

So today I received the F108N and along with the F105N I planned to change my oil, filter, and install whichever Fumoto valve had the correct thread size.

Looking under the car, I was surprised that there wasn't more plastic undercladding. The oil pan is exposed, nestled between exhaust and sway bar. Notably it's very deep where the drain plug goes, so it's great that it's not a big flat pan. It should drain well.

476192


14mm Drain plug, was pretty tight. For 2022+ Subaru has changed the OE drain plug to 17mm head - same thread. (NOTE - I did not have this problem but several owners have rounded their drain plugs. Only use a 6 point socket for removal) After removing it, it appears that the inside of the pan was painted while the drain plug was in. It shows what parts of the thread are actually in the pan and where it's only in the oil. The thread matches the F108 and the F108's threads are short enough that it will not cause excess oil to remain in the oil pan. We can put that concern aside.

476193


Ok, time to install the F108N but oh no! It won't rotate! The exhaust heat shield prevents the valve body from rotating and letting me screw the whole thing in. Oh well. I'm not prepared to remove the exhaust heat shield today just for the sake of the Fumoto valve. OEM plug put back in. Will consider whether removing exhaust heat shield or trying the F108SX makes more sense at the next oil change. At least F105 in any variant is definitively ruled out no matter what specs say on the web, for the 2020 Outback 2.4 XT

476194


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OK put in the Wix 57055XP (27psi bypass valve) and new full synthetic 0w-20 SN-Plus Dexos 1 gen 2 oil in using the special funnel.
(as of 2023 the current specs are ILSAC GF-6, API SP, Dexos 1 Gen 3)

Additional notes:

Oil level was at least half a quart high from the dealer. After 675 miles, oil level doesn't appear any higher or lower.

With both engines off overnight, compared the smell of a 2009 Honda Fit's several thousand miles old oil, and the 2020 Outback's 675 mile old oil.

Both had some gasoline smell, but nothing alarming, with the Fit oil smelling more "used engine oil" smell. It was quite dark. The Outback's oil was still light brown on the dipstick. Changed it anyways for the sake of identifying the correct Fumoto valve. When in the drain pan, the Outback's oil didn't look so golden. It was surprisingly dirty looking. Oh well. Not sending in a sample for analysis. F105N has wrong thread. F108N does not fit - will not screw in.

Next step will be to buy the F108SX and try again at the end of January, or maybe consider removing exhaust heat shield to salvage the F108N. If I could screw it all the way in, it would fit. Only question would be where the valve control would end up. There's not much space there for it to be accessible unless it's in the right position. Makes the F108SX seem very promising.
 
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#3 · (Edited)
What's the deal with that special funnel?

From the picture it looks like the exhaust shield could be lightly filed and create enough room to install the valve. Is that an optical illusion?
The funnel just screws into the oil filler threads to make things tidy and easy. There are at least two versions sold on Amazon that seem like they're from the same factory under different names.


Yes the heat shield could be nibbled or filed to make enough room, but I didn't want to hassle with that right now. The interference was maybe a 1/4" overlap. If it had been 1/8 I would have just bent it back with pliers or something. It could still be done, but depending on where the F108 ends up with it's fully screwed in, the valve body might be inconvenient to use since it's so tight.

The F108SX looks like a guaranteed fit and the benefit is that it can be rotated so that the control and nozzle are facing where you want. F108SX: Position Adjustable Oil Drain Valve with M16-1.5
 
#5 ·
I just ordered the F108SX and one of those plastic nipple things so I can attach a hose to it after installation. I can't justify changing the oil the moment it arrives, so I won't be putting it in until at least the end of January. Hopefully someone else contemplating Fumoto use will be able to verify and document the SX fitment before then.
 
#7 ·
Thanks for blazing this trail for us, Silver. You likely just saved a lot of folks from buying the wrong valve.
Initially I was thinking that maybe an extension would work but that would just add another potential leak point and lower the valve for higher potential to hang up.
I think your right, the third time will be the charm with the SX.
p.s. Great detail as always!
 
#8 ·
I had expected it to look like the Ascent, with large plastic undercladding with just an opening for draining the oil, or a plastic oil drain door found in other Subarus. With so little undercladding under the car, it didn't seem as if there were obvious unused mounting points, but I thought there was a chance someone would chime in and say "hey I have undercladding there".

Thinking that maybe the aluminum undertray covers more, I looked at the instructions for mounting it, which requires drilling holes.



It confirms that the original undercladding is just the way mine is, and surprisingly, the aluminum one doesn't replace the plastic one, but fits over the plastic one and only covers the central part of it.

https://subaruonlineparts.com/docs/E515SAN000.pdf
 
#9 ·
So today I received the F108N and along with the F105N I planned to change my oil, filter, and install whichever Fumoto valve had the correct thread size.

Looking under the car, I was surprised that there wasn't more plastic undercladding. The oil pan is exposed, nestled between exhaust and sway bar. Notably it's very deep where the drain plug goes, so it's great that it's not a big flat pan. It should drain well.

View attachment 476192

14mm Drain plug, was pretty tight. After removing it, it appears that the inside of the pan was painted while the drain plug was in. It shows what parts of the thread are actually in the pan and where it's only in the oil. The thread matches the F108 and the F108's threads are short enough that it will not cause excess oil to remain in the oil pan. We can put that concern aside.

View attachment 476193

Ok, time to install the F108N but oh no! It won't rotate! The exhaust heat shield prevents the valve body from rotating and letting me screw the whole thing in. Oh well. I'm not prepared to remove the exhaust heat shield today just for the sake of the Fumoto valve. OEM plug put back in. Will consider whether removing exhaust heat shield or trying the F108SX makes more sense at the next oil change. At least F105 in any variant is definitively ruled out no matter what specs say on the web, for the 2020 Outback 2.4 XT

View attachment 476194

View attachment 476195

OK put in the Wix 57055XP (27psi bypass valve) and new full synthetic 0w-20 SN-Plus Dexos 1 gen 2 oil in using the special funnel.

Additional notes:

Oil level was at least half a quart high from the dealer. After 675 miles, oil level doesn't appear any higher or lower.

With both engines off overnight, compared the smell of a 2009 Honda Fit's several thousand miles old oil, and the 2020 Outback's 675 mile old oil.

Both had some gasoline smell, but nothing alarming, with the Fit oil smelling more "used engine oil" smell. It was quite dark. The Outback's oil was still light brown on the dipstick. Changed it anyways for the sake of identifying the correct Fumoto valve. When in the drain pan, the Outback's oil didn't look so golden. It was surprisingly dirty looking. Oh well. Not sending in a sample for analysis. F105N has wrong thread. F108N does not fit - will not screw in.

Next step will be to buy the F108SX and try again at the end of January, or maybe consider removing exhaust heat shield to salvage the F108N. If I could screw it all the way in, it would fit. Only question would be where the valve control would end up. There's not much space there for it to be accessible unless it's in the right position. Makes the F108SX seem very promising.
ZX:

Great write-up! Thanks for posting.
 
#12 ·
that funnel you got there is pretty nifty looking. I use an older funnel I've had that's older that some people on the forum here... but it isn't threaded and can move. If you were really thrifty, and wanted a threaded funnel (that screws in and fits and holds itself in place), you could do something like this, just cut the bottom of the container off:

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That one has a thicker plastic than a 2 liter cocacola container (as an example)

Other containers have the same threads on them - some deeper than others. The gallon size jugs (like some ammonia, bleach, etc) are too wide and may not fit depending on application. All these would work (the vegetable juice one might hit a 3.6R cover)... the powerade and containers like that are a bit thinner than that bai whatever thing is

476253
 
#27 ·
I just received the Fumoto F108SX but won't be installing it until the end of the month. Has anyone else already installed one successfully?
 
#32 ·
I don't think I mentioned this before, but during the first oil change, I fished around the oil with a neodymium magnet and it didn't pick up any sludge or flecks - so if there was anything, it was captured by the OEM oil filter. I hate to drain and refill with the same fluid. It just doesn't feel right to me despite knowing it's just fine. It feels like spitting out water and then drinking it.

My dealer still hasn't done the WUU6 for my car.

Meanwhile since I had the new phone mount, I used an old Kiwi PLX bluetooth thing and Torque Pro, captured approx 14.7 PSI boost - didn't really give it a full run so it could be higher at Max.
 
#33 ·
I must have a special 2020 Outback Limited XT. The oil drain plug was 15mm and the Fumoto 108N fit but it took a little coaxing. Actually I took a hammer to the top lip of the heat shield. I didn't have to bash the crap out of it, just enough to allow the valve to fit past it. It doesn't take much and its not all bent to hell either. I will have photo later.
 
#34 ·
I must have a special 2020 Outback Limited XT. The oil drain plug was 15mm and the Fumoto 108N fit but it took a little coaxing. Actually I took a hammer to the top lip of the heat shield. I didn't have to bash the crap out of it, just enough to allow the valve to fit past it. It doesn't take much and its not all bent to **** either. I will have photo later.
I believe you... on mine the overlap was about 1/4" so it was doable. I have the 108SX now but not installed.
 
#36 ·
On February 8th I will attempt installation of the F108SX unless someone else chimes in that they have already done the install and can confirm fitment.

I'd rather delay this because I changed my oil only 1 month 1000 miles ago, but if nobody else has done it, I'll go ahead and document it on February 8th. Will also be switching to 0W30 at my next oil change and will report back if there's any subjective difference in feel, e.g. start/stop smoothness, etc.
 
#38 ·
Yes..... I'm also interested in switching to the higher viscosity just for kicks. But you're right - it's silly to waste good oil, and once the fumoto is in, the next oil change will be insanely easy. Not that it's hard to remove a drain plug, but flipping a valve takes zero tools, no crush washers, wiping the bottom of the oil pan, and other stuff. I plan to drain directly into bottles using the hose from the fumoto next time.

After draining if the oil looks good I'll put it back in. If it looks dirty (yes I know it's still good but...) then I'm dumping it.
 
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#39 · (Edited)
Watching videos on the Fumoto units people speculate it doesn’t allow all the oil to drain because it wont screw flush to inside of oil pan.
1. How can this be tested?
2. If Fumoto systems always leave a small amount of used oil in bottom of the pan what effects will that have long term?
3. If there is oil left over every change, is that a game changer for anyone?
 
#40 ·
Watching videos on the Fumoto units people speculate it doesn’t allow all the Oul to drain because it wont screw flush to inside of oil pan.
1. How can this be tested?
2. If Fumoto systems always leave a small amount of used oil in bottom of the pan what effects will that have long term?
3. If there is oil left over every change, is that a game changer for anyone?
I documented this early on with the original post. The threads in the Fumoto don't dive deep into the oil pan, it does screw in flush. It's not holding back oil. The benefit to the Fumoto is that it makes changing oil so ridiculously easy (especially with the oil filter on top instead of underneath) that oil changes aren't put off, and you can easily do it yourself with no tools, no worrying about crush washers, and you can (if you get the nozzle type and a hose) drain it directly into a container with no splash at all.

Even if it did leave 1/4 cup of oil in the pan (it doesn't) that wouldn't matter unless there was something serious contaminating your oil (like coolant) in which case you wouldn't just do normal oil changes.

477958
 
#45 ·
Hi I am new to the forum, and purchased a 2020 Outback Limited. It is my first Subaru. I can do some mechanical work and enjoy doing my own oil changes. Would you review for me the correct Fumato valve to buy. I have the 2.5 L non turbo engine. Any other tricks I should know about in terms of oil changes? Thanks, Frank (closest dealer is 1.5 hours away and a hassle to schedule oil changes)
 
#48 ·
According to the Fumoto website, any F108 series will fit your 2.5 engine.


If it were me I would get the long nipple version F108N and use a hose, but look under your car first to see if it will hang down too much.

If you're planning to go through deep mud and a lot of off-road you can stick a cap over the nipple to prevent stuff from getting lodged in there.

Vinyl caps are available at every auto parts store, but Fumoto sells them as well

 
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#49 ·
I wish I had free oil changes for the first 24k miles. My dealer doesn't offer that. They're conveniently located 5 minutes away from me.
 
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