Yes and no. They are supposed to be replaced. But if you don't it will be fine. The biggest difference is that you need to tighten old ones more - but don't strip the pan . . . I've been replacing mine for a few years, but I have a lifetime previous to that when I did not . . .

 

It realy one of those thing that you should change everytime. Just like underwear...

 

I rarely change those crush washers. You'll be fine not changing it.

 

I always change it. Peace of mind. No Subaru dealer nearby? A couple just tossed em to me no charge.

 

Any decent dealer will toss in a crush washer when you get a filter.

 

I can't say I've ever purchased a filter from a dealer, for any car I have ever owned.

 

I don't run Subaru oil filters cause apparently they switched suppliers like 5 years ago and they use a cheaper filter element now.

I buy my washers in bulk at the dealer and run Mazda oil filters as the Mazda filters are apparently identical to the old Subaru filters:

To O.P: Not changing the washer will be 'fine' but don't make a habit of it cause it's obviously better to change them.
You should stock up on oil/ filters/ washers in case they are ever backordered cause you don't want to be in a pinch.
I buy like 4 filters at a time, and washers by the bag, and I buy my oil by the case for that very reason.
When the last bottle/filter/washer gets used, I'm sure to stock up so that I have 3k/6 months incase there is a delay.


EDIT: Just looked up the Mazda filter and came across this on importimageracing: "Miss that original Tokyo Roki filters Subaru use to supply here in the USA? Have no Fear, Mazda to the rescue. Yes you heard correct, Mazda ROKI oil filters are the same as the original oil filter that came in your WRX and STI back in the early 2000s. Just slightly larger. Why do you want it you ask? The blue filters Subaru uses here in the states aren't as good of quality as the original black Tokyo Roki filters. The extra oil capacity and filtration also helps a lot."

 

I ran the larger Tokyo Roki filter... Nothing particularly special about the filter, other than it was bigger. The stock filter is too small and I've had customers have the OEM filters drop pressure after a couple thousand miles, install a new OEM and the pressures comes back up. I literally do not think I ever changed the crush washer, the entire 10 years I had my STi, or even the 218,xxx miles I've put on my Jeep.

 

The stock filter is too small and I've had customers have the OEM filters drop pressure after a couple thousand miles, install a new OEM and the pressures comes back up.

I'd love to hear more on this and how the the testing was done and data collected. I have a lot of data showing otherwise on the factory blue filters.

If we were comparing the factory BLACK filter (that come on the EJs from the factory), they are a very different filter. I do not recommend them for anything beyond 1,000 mile break-in. I see people all the time saying "I use the black, because that's what comes on the engine", but those filters have less than half of the filter media of the blue. The short of it is that most any replacement filter is fine if you're performing appropriate OCIs, given the use and application. Do not recommend the 'performance filters' as they have horrible filtration. K&N for example has 90 micron filtration vs 5 microns for the OEM blue. The K&N makes sense if you're changing oil after each drag pass, or dual filters, but not much more.

If you think the OEM blue is the same as an orange Fram because they come out of the same factory (some do), or out of a Honeywell factory, you're mis-informed. That's like saying a base Impala and Caddy are the same because they come out of the same factory. OEMs that make components, like filters, have different filter media specs, tolerances, quality control, and even allowable performance criteria. I used to think the same, until I was employed at in engineering department at an auto OEM. It was an eye-opening experience. OEM, OEM replacement, aftermarket replacement, and performance replacement parts, depending on the parts were made on the same or different tooling, but ALL had variations in tolerance and performance... some even in allowable tool wear for the manufacturing components.

 

Completely unnecessary to replace

 

I really cant believe you guys dont change the crush washer when you do an oil change. Thats like oil change 101. Its literally $1 washer when you get your oil filter at the dealer. Just imagine having an oil leak because you didnt replace the washer. Or worse, stripping the pan because you have to crank down on the drain plug becuase you dont want to replace the crush washer.

You know, you can get a whole box of subaru oil filters and washers for less than $100. This way you'll have a an oil filter and crush washer every time.

 

I also usually just use a new crush washer once per vehicle, but it’s with a fumoto valve…

Really though, gasket reuse depends on the resiliency of the material, and how uniform a surface you’re sealing. In this case the first one… well I mean “crush” is in the title. However it’s just so small and smooth that it can work, but for the price I’d just buy some washers if I was still using the plug.

 

This is a really nitpicky thread and in that vein I'll say that since I spend $ and time on good oil and low OCIs, use new crush washers (not that I really think I need to) and let my warm oil drain completely, means that I don't add parts that will add millimeters to the level of oil that can be drained. Yeah, its a nit pick, but I own wrenches and I'm not afraid to use em.

ADED: yes to KB below.

 

This is a really nitpicky thread and in that vein I'll say that since I spend $ and time on good oil and low OCIs, use new crush washers (not that I really think I need to) and let my warm oil drain completely, means that I don't add parts that will add millimeters to the level of oil that can be drained. Yeah, its a nit pick, but I own wrenches and I'm not afraid to use em.

I will counter nitpick that a few mm of oil level is likely negligible (with enthusiast frequency oil changes, not like we’re draining an acidic slurry that’s been in there 10k miles), along with all the oil clinging to surfaces that doesn’t come out. maybe I’ll shim one of the ramps next time to counter act this.

 

I run the WIX XP filter.

 

^^^^ but do you replace the crush washer when doing an oil change?

 

I did not at 1000 mile change. Changing oil again tomorrow myself w/ new plug and gasket.

 

No one else has ever reported that, except when the media is saturated, because of impending doom, or a filter is defective. Both of which you can find instances of for most any filter out there if you look hard enough. If the filter caused that, why? Did you perform an autopsy? With it going from good to bad quickly like that, it could be a couple of things.

The bypass filter almost never opens, except at startup when the engine is dead cold and for a very short period of time. Otherwise, it NEVER EVER opens. Not with 0w20, 20w60, idle, 9,500RPMs, 900whp, and not even with a ridiculously long 7,500 OCI on a healthy engine.

 

This was actually on my car.

Started it up one morning and my cold start OP was ~70 psi. I thought it was the gauge malfunctioning, so I just went on my day. Noticed the hot OP would never exceed 55 to 60 psi, and decided to do some googling and the thread here(Lower cold-start oil pressure - NASIOC) from another member on here prompted me to swap my oil filter for a new one.

once I did that, my OP is now back to normal pressures. I dissected the oil filter in question and didn't notice anything out of the ordinary. the relief valve still functioned and nothing was clogged up.

 

You might be able to get away without replacing it but unless I have no other choice, I would change it. Reason is simple, if you compare a new vs. used OEM washer, it is painfully obvious why it is appropriately named "crush washer". Look at it this way, in an unlikely situation that it does develop a leak, you will have to go back and re-do the oil change. When it comes to cars, regardless if it is modification or just maintenance, I try to follow the simple rule of "Do it once and do it right."

 

How are you testing the bypass in the filter? It should be expected crack open, often actually (I know we had this conversation before and you didn't really answer this question in a manner of actually testing this, which is why I'm dreading even responding here). I've got a good friend, who used to be a Ford engineer, even on the old SHO who originally taught be a lot about this stuff. He even showed me how a SHO oil pimp can outflow an FL-1A filter (about 3-4 times bigger than a stock filter... Which was already much bigger than the Subaru filter), and he resorted to running two of these large filters.

Horsepower does not matter here... No need to reference it.

 

How are you testing the bypass in the filter? It should be expected crack open, often actually (I know we had this conversation before and you didn't really answer this question in a manner of actually testing this, which is why I'm dreading even responding here).

Pressure differential. The OEM blue has a 29psi bypass pressure, which is unusually high. This is one of several reasons why I recommend the OEM blue. Most engines use a filter bypass in the 12-18psi range. Subaru is different here. The Suby blue filter also has a crap load of media in that small filter, which ultimately dictates flow and resistance to flow. My C63 which has an engine 2.5 times bigger, has less filter media and the filter is ~ 2 times as tall. There are few non-OEM EJ25 filters that meet this bypass spec. Most are in the more traditional 12-18psi range. How that plays out is not for me to speculate, but anyone performance minded is doing regular oil/filter changes long before the media has enough pressure drop to bypass. Few filters meet the same OEM bypass spec, but WIX is one of them. Most do not.

We've built a pretty good selection of sensors for our dyno cell and measure pressure at several locations on the block, as well as flow. We know exactly what's happening with the filter's bypass, the oil pump regulating bypass, crankcase pressure, and flow.

Horsepower does not matter here... No need to reference it.

Agreed, I said that because not everyone may have know that.

Anyone is more than welcome to reach out to us and ask questions. We don't publish everything we do, as a lot of it is data for us... Like when we test everyone else's sumps, pickups, baffles, pumps, headers, AOS, intercoolers, etc... We don't publish very much because we have good relationships with our competitors. For example, we've sent an oil pan to Perrin so they can test fit headers. You might say Frenemies

 

I know how a filter works. Exactly HOW are you testing? I suspect your testing pre and post filter differential, no? If so, the post-pressure is the sum of the parallel paths (media and bypass).

This is were we got last time and I basically said the same thing.

 

I know how a filter works. Exactly HOW are you testing? I suspect your testing pre and post filter differential, no? If so, the post-pressure is the sum of the parallel paths (media and bypass).

This is were we got last time and I basically said the same thing.

Pressure pre and post filter shows the pressure drop caused by the filter. If the pressure drop is high enough, the bypass opens. Can be cause by excessive viscosity (cold), or poor filter flow due to excessive contamination.

IDK what you mean by parallel paths.

 

I thought for sure the OEM bypass pressure was 23psi, no?

 

Here's a quick plot of oil flow and oil pressure on our KBM built mule showing 11mm/shimmed vs 12mm/shimmed flow and pressure. For anyone who's curious...

 

I await your tests for delta across the media and bypass filter sensor.

Эксперимент читателя ABW.BY: масляный фильтр работает всего 2500 километров?

Чем лучше масляный фильтр будет очищать моторное масло от грязи, тем дольше прослужит двигатель, однако в конструкции фильтра предусмотрен перепускной клапан, после открытия которого в мотор поступает грязное масло, - экспериментально устанавливаем, когд

www.abw.by

 

Jason, c'mon... You're better than this. What car/engine? How many miles? What's the engine condition? What filter? What oil? Is it OEM filter or OEM replacement, aftermarket, etc? What are the engine's oil pump and flow specs? What are the specs for the oil filter? And no Suby enthusiast in their right minds drives their car at those cold oil temps; three miles from your driveway you'd be above that depending on ambient, but the OEM coolant gauge wouldn't even be in the normal range yet.

This article creates more questions than it answers. I can pull tidbits that completely support statements I've made AND yours. A neat piece of data for him, but not for us. He even says as much, "In any case, after a full warm-up in normal mode, the valve does not open, which means that the oil is filtered. What else do you need?" He also goes on to say that the backflow prevention valve does nothing. I don't know about you, but I' have never once spin off an EJ filter and NOT had oil come out of it.

I can see the pressure drop, and it's marginal. Pressure on BOTH sides of the filter is present. Knowing the spring force of the bypass you can calculate how many psi of pressure drop is required to even crack it open, even if you don't want to believe the OEM specs. The filter is a miniscule restriction when compared to the engine's oil clearances.

 

Yes, I know that many OEM's use small filters. They also recommend never changing transmission fluid, really long OCI's, resource conserving oil, etc.

In any case, all things equal, a larger filter will filter better due to more filter area, better filtering through the slowing oil through the media, hold out longer in overall changer intervals... And far less likely to crack the bypass (crack, not fully open).

 

Yes, I know that many OEM's use small filters. They also recommend never changing transmission fluid, really long OCI's, resource conserving oil, etc.

In any case, all things equal, a larger filter will filter better due to more filter area, better filtering through the slowing oil through the media, hold out longer in overall changer intervals... And far less likely to crack the bypass (crack, not fully open).

So the Mazda filter is good then… I’ll just keep using that 😂