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2012 Forester X 5 MT
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Discussion Starter · #1 ·
I'm the curious type. I took apart my OEM oil filter at the first oil change at 7.5K and found it to be spotless - except for a couple of tiny red specs (gasket compound I suspect).

So I wondered how "gunked up" my filter would be if I let it go for 15K miles. The result was the same. Clean as a whistle except again for a couple of tiny red specs. No gunk.

Now I certainly am not going to be able to see 25u particles stuck in the filter medium. They probably are there. But I suspect that if there were an appreciable amount I'd see a film or paste or some hint of their presence.

Anyway, just an experiment. FWIW. And, this is a Roki -130 filter.
 

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2014 2.5i Touring CVT
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Must admit, looks to be in pretty good shape. To be honest, I would not want to push this filter any further, not worth the gamble. The way I see it, better just to use a fresh oil filter each oil change, piece of mind. Must say, the information is interesting.
 

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2013 Forester Automatic
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Used Oil Analysis will answer your question about how long is long enough. I used to run a Ford Modular filter at least 15,000 miles (5000 was the recommended change mileage), and watched UOA's. Typically, the Insoluables would be 0.3 the first 5000 miles, and would drop to 0.2 the next 5000 and the subsequent 5000. I'd change the filter then due to being a year old, but, not because it was "used up". Cutting open the 15000 mile filter showed no visible difference than cutting open a 5000 mile filter.

Science has proven that a filter change at every oil change isn't needed on MANY vehicles.
 

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I would agree more so if the vehicle had a oil bypass set up, or an oil slinger setup. In many cases many of the diesels have these set ups to extend OCI and oil filter change intervals. Even with these things in place, it is best to get an UOA to ensure everything is within safe margins.
I am a first time Subaru owner, after owning a diesel pick up for many years. My Forester has the Dealer Life Time oil and oil filter changes. For those who change their own oil and oil filter, for the $5.00 price of the OEM oil filter, I can't see taking any chances.

Additionally, I am guessing if your vehicle is still under warranty or if you have an extended warranty, if an engine lubrication malfunction occurs, and if it was caused by an oil filter issue, you may be holding the bag if it is discovered the oil filter was not changed per Subaru's scheduled requirements. You can bet, that Subaru will do some investigation to see who's dime will cover the repairs.
 

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2015 Highlander AWD XLE 6AT
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I'm "old school", and the notion of 15K mile engine oil- and filter change intervals still scares me. However, extended OCI intervals is clearly where we're headed.

One key reason is environmental. As I understand it, many governments are putting pressure on auto manufactueres to reduce oil "consumption" by extending OCI's. Improved manufacturing processes, oil, and engine management should help in that regards.

Our 2006 Honda Accord was fitted with an oil life monitor. Its algorithm looked at several parameters (engine starts and others) to determine the engine oil's useful life. I seem to recall seeing one useful life calculation of almost 10K miles, based mostly on repeated long distance highway travel.

Our BMW uses a fairly sophisticated system to estimate its engine's OCI. The default is 15K miles, but can be adjusted down based on paramaters such as oil level, oil temperature, and the oil's electrical charateristics, which change as the oil degrades. BTW, this system will also issue an alert if the oil level is too high, and the 3.0 liter non-turbo engine is factory-fitted with an engine oil cooler.

However, when I do an oil- and filter change (7 U.S. qts.) on this car, I manually change the default limit setting from 15K miles down to 7.5K miles. That may not be the new target, but it's twice the old days' "Rule of Thumb".

HTH,
Jim / crewzer
 

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The oil filter on the Subaru's are not that big. I am guessing a small oil filter can only filter oil for so many miles without an issue.
 

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2015 Highlander AWD XLE 6AT
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Our BMW engine's oil filter (MANN HU816x) and Subaru's black -130 appear to be roughly the same size. However, both are indeed larger then the black -160 or the blue -15A replacement.

Regards,
Jim / crewzer
 

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Discussion Starter · #10 ·
...for the $5.00 price of the OEM oil filter, I can't see taking any chances...

...you may be holding the bag if it is discovered the oil filter was not changed per Subaru's scheduled requirements...
I'm not advocating doing a 15K filter change. I was curious. I thought others might be interested in my results.

As far as the warranty is concerned, I have a nice receipt for 12 filters that I bought a while ago. Who's to know how often I use them. You won't tell will you? :)
 

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The oil filter on the Subaru's are not that big. I am guessing a small oil filter can only filter oil for so many miles without an issue.
Correct. But, my semi-educated guess is that "many miles" is a lot farther than most people would imagine. If the engine is in good shape, the oil quality is good, the fuel and ignition system are good, and you aren't operating in severe conditions, I wouldn't be the least bit surprised if 50,000 miles wouldn't overload even one of these small filters.

15000 miles is as long as I've run a filter and cut it open to examine it. There was essentially almost nothing to be seen in the way of particulate matter....a few specks of carbonaceous-appearing particles, and a very small number of metallic specks. Modern engines are very clean compared to the "old days".
 

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Your right about engines of today being cleaner than engines of the past.The motor oils and oil filters have also come along way with quality.
 

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2012 Forester 2.5X Auto
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I wouldn't try this with one of the new "blue" oil filters…….horrible quality IMHO...
 
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