Subaru Oil Filter ByPass Questions & Filter Comparison

I see no value and very possible a downside in using a filter that doesn't met Manufacture specs. We don't have the data to counter the recommendation of the manufacture. Ed
 
I see no value and very possible a downside in using a filter that doesn't met Manufacture specs. We don't have the data to counter the recommendation of the manufacture. Ed
That would also seem to be saying you don't trust the large aftermarket filter makers to properly specify oil filters for these special cases like Subarus with an OEM filter bypass spec of 27 PSI. I doubt they are randomly specifying filters without some engineering research behind it. And as mentioned before, the actual design of the oil filter and its dP vs Flow performance has an impact on what the bypass valve setting is. Could be that the OEM Subaru filters have a high dP vs Flow curve, and/or Subaru thinks their drivers will be revving the engine high shortly after cold start-ups which is why their bypass setting is so high.
 
So Subaru says they will tolerate a 27 PSI drop across the filter before opening to additional flow? So how is 12 PSI (or similar) worse? Or harmful? Is it allowing captured crud back in to the engine?
 
So Subaru says they will tolerate a 27 PSI drop across the filter before opening to additional flow? So how is 12 PSI (or similar) worse? Or harmful? Is it allowing captured crud back in to the engine?

Captured particles don’t get injected into the engine when the bypass opens. With the valve open, some oil simply bypasses the oil filter media and goes back into the engine unfiltered.
 
Captured particles don’t get injected into the engine when the bypass opens. With the valve open, some oil simply bypasses the oil filter media and goes back into the engine unfiltered.
That could depend on the filter orientation and the location of the bypass valve, and where captured crud can deposit and settle in the can. That's why Ford came out with a base plate located bypass on filters that mounted base upward.
 
That would also seem to be saying you don't trust the large aftermarket filter makers to properly specify oil filters for these special cases like Subarus with an OEM filter bypass spec of 27 PSI. I doubt they are randomly specifying filters without some engineering research behind it.

But that’s exactly the point… I don’t trust these aftermarket companies. They spec a filter for your car based on a general size and thread type.

Take the Mazda Skyactiv engine for example. They are sensitive to oil pressure and will trigger a CEL and cause damage to the engine to the point that Mazda had to put out a service bulletin to the dealers to inform them to use the correct oil filter and not some other one just because IT FITS. 🤦🏻‍♂️😡

WIX also had to go and design an oil filter SPECIFICALLY for the Skyactiv engine because of this. 🤷🏻‍♂️

Why people would use random oil filters instead of the OEM spec is beyond me. 🤦🏻‍♂️

Most engines will be just fine though, I’m sure, and problems only rise in very specific cases.
 
Can we have a skyactiv bulletin copy posted here?

I use random filters. Never did have any problems with any vehicles including Mazdas with skyactivs.

Specific cases sounds like fear scare bull
 
But that’s exactly the point… I don’t trust these aftermarket companies. They spec a filter for your car based on a general size and thread type.
I was taking about the large aftermarket filter makers to properly specify oil filters for these special cases like Subarus using a bypass setting similar to the OEM filters - the filter makers that do specify filters for them that do have a higher bypass setting. I highly doubt any big name filter maker is just going to specify any oil filter solely based on the "general size and thread type". It's not hard to get a dP vs flow curve either by test and/or modeling for every oil filter model they make, and then ensure it will work on engines with oil pumps that put out the highest expected flow volume (worse care scenario).

I think a lot of these OEM filters with very high bypass valve settings are to take care of instances when the engine might be revved up pretty high before the oil gets warmed up. A filter with 25+ PSI of dP with hot oil would have to be super flow restrictive and/or almost totally clogged up with debris. Of course very cold thick oil is a factor in what dP is produced across the filter. Most filters only produce around 5-8 PSI of dP at 10-12 GPM when the oil is at operating temperature.
 
And it states nothing about bypass pressures, oil pressure sensitivity, causing damage to engines... and all that internet BS scare fear that too many push

It’s impossible to find anything from 10 years ago on the internet.

Mazda published that page back in 2013 or so when the Skyactiv engine rolled out and warned the tech’s to use the correct oil filter (even though the older filters looked the same and fit)

It’s nowhere to be found now and the only thing that shows up is this update they later released.

I’ve owned my Mazda 3 since they were released and remember seeing the warning about using aftermarket oil filters. They must have removed it. 🤷🏻‍♂️
 

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I hardly see how this is aftermarket issue, Mazda had to educate its own service centers on it.
Seems like they dropped the ball on making the specifications known to all.
 
None of the automakers that claim so-called filter problems ever list brands/pn's or failure specifics. Scare fear them into OE parts!
Its like their marketing department demands something from engineering to keep the parts department at the dealership employed. When a filter company has a failure, most will uprev the part, print a bulletin, or something concerning the issue. When an automaker blindly blames the aftermarket filter for failure, its a big secret and everyone must use the OE filter since we can't state what brand/pn caused failure.

Or, maybe the automaker spun off their parts division making it viable for its own profits, like loans... Must support the sister company as much as possible.

I think what we're seeing, and no one at an automaker will admit, is that engineers are retiring. I don't think the newer ones know what they are doing. I've run into this in industry often. And, its sad. Making drastic changes on a 'whim' or 'personal preference' and scaring all to think its great.

Ask yourself this.... every engine has a filter... with some unknown single/multi/nominal/absolute filtration requirement that someone at the automaker decided and agreed upon with engineering and cost accounting. That filter requirement is so good that VVT solenoids have 'screens' and are still clogging, crudding, varnishing, failing, or sludging, even with that automaker's recommended interval, oil type, and filter. And, some blindly believe that they are looking out for YOUR ENGINE's best interest.

I don't blindly believe that Subaru is infallible with their intervals, fluid recommendations, filter specs, or even manufacturing. That would just be silly or foolish. How often does history have to repeat itself before you make your own decisions.
 
"To avoid engine damage", is a chickenshits brainwashing ******** statement, for the paranoid. Eventually, you'll need to make sure you buy dealer sourced air for your ICE engines.

Specifically what damage do Mazda's filters cause? And, you want to use it!
 
"To avoid engine damage", is a chickenshits brainwashing ******** statement, for the paranoid. Eventually, you'll need to make sure you buy dealer sourced air for your ICE engines.

Specifically what damage do Mazda's filters cause? And, you want to use it!

If someone is trying to fear-monger while directing the information only at Mazda dealer service departments, they are doing a pretty bad job.

It's perfectly reasonable to not include specific damage information on a TSB because it's not really all that relevant. They have determined that using the wrong filter poses a problem, this has clearly been tested and verified and is why the TSB went out. I'm sure Mazda has a tech line they can call to get the details if any of their employees wished to do so.
 
Except, you know... The part where it says just that

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Rather than it being filtration or bypass related, is it possible that the mounting flange and/or threads have a different depth, preventing full engagement of the o-ring, or maybe not long enough leaving the threaded part too short to fully engage the threads?

Without any information from Mazda, this entire thread is pure speculation, since it doesn’t appear that any of the aftermarket filter manufacturers have removed the appropriate cross-references to avoid lawsuits? Seems like if there were engine failures caused by aftermarket filters, Mazda would kick this into their laps, and there would be class-actions all over the place?
 
Rather than it being filtration or bypass related, is it possible that the mounting flange and/or threads have a different depth, preventing full engagement of the o-ring, or maybe not long enough leaving the threaded part too short to fully engage the threads?

Without any information from Mazda, this entire thread is pure speculation, since it doesn’t appear that any of the aftermarket filter manufacturers have removed the appropriate cross-references to avoid lawsuits? Seems like if there were engine failures caused by aftermarket filters, Mazda would kick this into their laps, and there would be class-actions all over the place?

I have no idea what is different about it. All I'm saying is the manufacturer probably has a reason for the TSB, and it's probably not driven by fear.
 
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