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2017 Forester Touring
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Discussion Starter · #1 ·
I have a 2017 Forester 2.5 Touring. Is there any harm (or benefit) to pouring fresh oil down the hole where the oil filter screws on? I was going to saturate the oil filter and then pour the excess down this hole, which leads to the oil pump. It seems it might provide lubrication to the engine just a few seconds quicker than just installing a dry filter.
 

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2011 Subaru Forester
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Zero need. Even when you drain the oil there is still residual oil coating parts of your engine. What you should do is coat the oil filter gasket with a bit of oil to prevent it sticking and ensure easier removal. But, filling a top mounted oil filter is asking for a mess
 

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2001 Forester S, 4EAT
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There is only anecdotal evidence that there is benefits of doing this. In fact there are plenty of vehicles that do not have the inverted oil filter can, so you cannot even presoak the filter as you suggest. Some vehicle use a filter without the can and that is attached to a screw top cap that screws into the oil filter housing.
 

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2017 Forester Touring
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Discussion Starter · #5 ·
Zero need. Even when you drain the oil there is still residual oil coating parts of your engine. What you should do is coat the oil filter gasket with a bit of oil to prevent it sticking and ensure easier removal. But, filling a top mounted oil filter is asking for a mess
I know to coat the rubber gasket with a film of oil. I was not going to try to install the top mounted (inverted) oil filter filled with oil. I was going to put enough oil in the filter to saturate the filter material, and pour any excess (if any) into the hole and then fill the hole. This is probably overkill, but I was wondering if anyone had any specific info whether this is beneficial. I've never done it - just wondering.
 

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2017 Forester Touring
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Discussion Starter · #6 ·
There is only anecdotal evidence that there is benefits of doing this. In fact there are plenty of vehicles that do not have the inverted oil filter can, so you cannot even presoak the filter as you suggest. Some vehicle use a filter without the can and that is attached to a screw top cap that screws into the oil filter housing.
" . . . vehicles that do not have the inverted oil filter can, so you cannot even presoak the filter as you suggest." Huh? You can preSOAK (not fill - just get the filter element SOAKED) any oil filter, but you can only FILL and install a bottom mounted oil filter. You can't FILL and install a side mounted or bottom mounted filter without making a real mess.

I had a 2008 M-Benz diesel that used an oil filter insert and a reusable cap.
 

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Discussion Starter · #7 ·
You are thinkin too hard. Lots of cars have top mounted oil filters. This has never been an issue.
I have always changed the oil in my vehicles over the years. I have never actually filled the hole and soaked the inverted filter. I was just wondering whether there was any real benefit to doing it.

I also use a "fishing" magnet that can lift 260 pounds on the top of the metal can of my inverted oil filter. I kind of figured that magnetic drain plugs on differentials and transmissions are beneficial, why not on the oil filter? Wadda ya think?
 

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2012 Forester 4 speed auto
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You might disable the fuel pump by pulling the fuse and then crank the engine until the oil pressure warning light goes out. This will put oil into the filter and the anti drain back baffle will keep it full of oil even if it is inverted.
 

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Discussion Starter · #9 ·
You might disable the fuel pump by pulling the fuse and then crank the engine until the oil pressure warning light goes out. This will put oil into the filter and the anti drain back baffle will keep it full of oil even if it is inverted.
Makes sense. Engine gets lubed without the stresses of combustion.
 

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2022 Forester 2018 Forester XT
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I had a Ford Ranger which had a semi inverted filter with no anti drainback valve and it was a huuuge filter. Every time you started it the engine made a racket for 10 seconds. 230K miles later it was still on the road.

So I will be the 3rd member here to say you are wasting your time.
 

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2020 Sport
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You might disable the fuel pump by pulling the fuse and then crank the engine until the oil pressure warning light goes out. This will put oil into the filter and the anti drain back baffle will keep it full of oil even if it is inverted.
there is a clear flood mode where you press the gas to the floor and crank it supposedly the oil pump will circulate the oil. I am not convinced that the new oil filter needs to be primed either.
 

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I think attaching a strong magnet to the filter risks interfering with a sensor or two. If you had enough metal circulating in your engine for that to be beneficial, I think the engine would be on its last legs. Just change your oil regularly and use a good filter-- ideally a Subaru one.
 

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2001 Forester S, 4EAT
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" . . . vehicles that do not have the inverted oil filter can, so you cannot even presoak the filter as you suggest." Huh? You can preSOAK (not fill - just get the filter element SOAKED) any oil filter, but you can only FILL and install a bottom mounted oil filter. You can't FILL and install a side mounted or bottom mounted filter without making a real mess.

I had a 2008 M-Benz diesel that used an oil filter insert and a reusable cap.
I also drive an ML 350 Bluetec. I was implying that it's not practical to use the OP's method of prefilling the oil filter and then pouring the oil into the filter housing with our oil filter insert since there is no "can". I was also suggesting that this practice of "prefilling" is not a useful practice.
 

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You might disable the fuel pump by pulling the fuse and then crank the engine until the oil pressure warning light goes out. This will put oil into the filter and the anti drain back baffle will keep it full of oil even if it is inverted.
This is a misunderstanding. The anti drain back valve (baffle) only keeps the dirt/particles on the dirty side of the oil filter from draining back down into the engine. All of the oil still drains down the middle of the filter. With the top mounted oil filter, every start is a dry start until the oil is pumped through the filter again.

Like @adc said, its a waste of time prefilling the oil filter.

StanF

p.s. if you want to put a magnet ontop of your filter - go ahead but its a waste of time too. Not necessary since the metal particles will be trapped in the filter media.
 

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2021 Forester Limited
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As far as the magnet, it would be better served on the side of the can, not the top. I doubt oil sees the top immediately, as there will probably be trapped air that isn't pushed out, unless the media is blocked that far up. The air will probably be gradually worked out as the engine runs, as the rpm's vary the oil flow and pressure inside the can.

The oil travels from the outer part to the inner part, so the magnetic field would see unfiltered oil. But it isn't going to collect any non magnetic aluminum bits, and only the stuff that is small enough to make it past the filter media would be of any benefit.

And if it's that small, is it going to do any real damage?

Then there is the bypass valve. If the magnet has collected a bunch of crap, and the bypass valve opens from say really viscous cold oil, and said oil takes a chuck of the outer reaches of magnetic goo with it....
 

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There is just narrative proof that there is advantages of doing this. Truth be told there are a lot of vehicles that don't have the modified oil channel can, so you can't even presoak the channel as you recommend. Some vehicle utilize a channel without the can and that is appended to a screw top cap that screws into the oil channel lodging
 

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2017 Forester Touring
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Discussion Starter · #17 ·
All the responses make good points. Thanks for your observations and insights.

I average 10,000 miles a year and change oil (Amsoil Signature series) and filter (Wix) once a year. It takes less than 30 seconds to saturate the filter element and pour some oil down the tube that feeds the oil pump, thus priming it and delivering oil to the system a few seconds earlier. Given the problems Subaru’s boxer engine had in (hopefully) the past, I think I'll start doing it, even though I will never really know if it helped.

Re the magnet, I learned that placing a magnet on top of the filter is useless. Magnets should be placed on the sides to attract and hold ANY size ferrous particle before the oil flows through the filter element. Wix has a good video on oil flow through a filter. This only takes about 10 seconds and should leave the filter element cleaner, which means cleaner, better oil flow. Think of the sludge on the engine, transmission and differential magnetized drain plugs, and these are not subject to combustion residue!

As a retired ol’ phart, I don’t mind investing about 40 out of 31.6 million seconds in a year for the obvious benefit, even though it may not be LARGE and can’t be precisely quantified.
 

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Discussion Starter · #18 ·
All the responses make good points. Thanks for your observations and insights.

I average 10,000 miles a year and change oil (Amsoil Signature series) and filter (Wix) once a year. It takes less than 30 seconds to saturate the filter element and pour some oil down the tube that feeds the oil pump, thus priming it and delivering oil to the system a few seconds earlier. Given the problems Subaru’s boxer engine had in (hopefully) the past, I think I'll start doing it, even though I will never really know if it helped.

Re the magnet, I learned that placing a magnet on top of the filter is useless. Magnets should be placed on the sides to attract and hold ANY size ferrous particle before the oil flows through the filter element. Wix has a good video on oil flow through a filter. This only takes about 10 seconds and should leave the filter element cleaner, which means cleaner, better oil flow. Think of the sludge on the engine, transmission and differential magnetized drain plugs, and these are not subject to combustion residue!

As a retired ol’ phart, I don’t mind investing about 40 out of 31.6 million seconds in a year for the obvious benefit, even though it may not be LARGE and can’t be precisely quantified.
Oooops. The engine drain plug is subjected to combustion residue.
 

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It's your time to spend as you see fit..
No one is telling you what you should or shouldn't do.
Will your technique hurt?
Nope.
Will it help?
Likely not as the upside down top mounted filter is empty every time you start the car.
Is there an oil filled passage below the filter after it has drained out, just like when you are changing the filter before you prime it?

Perhaps the difference is in the pre-soak.
Would that make a difference?
If you think it does, by all means do it, but that doesn't mean it actually makes a difference, let alone a significant one.

A point to consider is that it isn't a commonly recommended practice.
 

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Discussion Starter · #20 ·
"... the upside down top mounted filter is empty every time you start the car. " What about the rubber or silicone retention valve? Isn't that supposed to prevent "dry" starts? And a new filter is super dry, which is what led me to believe a saturated filter element and a filled tube leading from the filter to the pump might be beneficial. Granted that is only a once-a-year occurrence (for me) at oil and filter changes, and not each time the car is started, so the benefit would be minor and not recurring. Over the life of the car, or my ownership of it, it likely won't mean a thing.

Putting a strong magnet on top of the oil filter was a bad idea. It likely pulled on the bypass coil or leaf spring, increasing the pressure needed to bypass the filter, if a bypass was needed.

Anyway, it was an interesting thread.
 
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