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Discussion Starter #1 (Edited)
I got some Pennzoil oil and filter on sale at Autozone. The Fram ExtraGuard filter they gave me looked shorter than Subaru original, so I picked up a longer filter instead (same width).

I change oil every 6 months on my car, so I guess a bigger filter should be able to hold more contaminants :confused:

When I changed oil in my wife's 09 Legacy, I also got a Mobil1 m1-110 filter which is longer than oem. That's the filter I used for my previous car (Nissan Maxima).
I'm planning to change her Legacy's Mobil1 synthetic oil & filter once a year (every 8-10k miles).

Is there any disadvantage of using a bigger oil filter than oem ?
 

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Problem is that the longer one is (for me) too close to the donut exhaust header. Before you do 8K miles on an oil change do an oil analysis. Blackstone Labs
 

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I got some Pennzoil oil and filter on sale at Autozone. The Purolator filter they gave me looked shorter than Subaru original, so I picked up a longer filter instead (same width).

I change oil every 6 months on my car, so I guess a bigger filter should be able to hold more contaminants :confused:

When I changed oil in my wife's 09 Legacy, I also got a Mobil1 m1-110 filter which is longer than oem. That's the filter I used for my previous car (Nissan Maxima).
I'm planning to change her Mobil1 synthetic oil & filter once a year (every 8-10k miles).

Is there any disadvantage of using a bigger oil filter than oem ?
I use WIX or NAPA Gold oil filters (made by WIX) in my Foresters. I use a larger 51334/1334 filter in the '03X, but it won't fit in my '07 FSXT, so I have to use the 51365/1365. :frown:

Bobby...


My MODding Journal
 

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Discussion Starter #6
Before you do 8K miles on an oil change do an oil analysis. Blackstone Labs
I will be changing synthetic oil every 8k in my wife's new Legacy which is a lease, so I'm not worried about that car.

In my 04 Forester I'm going to change dino oil every 6 months/3500 miles.
I'm going to do an oil analysis after the next oil change.
 

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Discussion Starter #8

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Thanks !

By the way, is it very important to have oil filter with "anti drainback valve" ?
The Fram Toughguard that I got doesn't have one.
I understand that anti drainback valve is needed if the filter gets clogged up completely. If I will be changing oil every 3k miles I shoild be ok ?
You have your valve names wrong. The anti drainback valve is a diaphragm that seals the inlets of the filter when the engine is off to keep the filter full of oil. The ensures that you get oil to all engine parts quickly.

The relief valve is the one that lets oil bypass the filter element when it gets totally clogged or may come into play if, on a really cold start, the filter element can't pass enough oil. As far as I know, every filter has a bypass valve, but the pressure settings where the valve releases may vary a bunch. Subaru OEM filters use a high psi setting and most aftermarket filters seem to be generic and have a lower psi setting.

I prefer not using Fram filters; they are built too cheaply inside. Sadly, this includes the new blue Subaru OEM filters, which are made by Honeywell/Fram. I have a stash of the old Tokyo Roki filters, the black OEM ones, which will get me through a while. I'm doing about 7k mile changes using full synthetic oil in an '09 X. I do like the idea of larger/longer filters and may consider them when I deplete my stash of OEM black filters. On a lease car, I would stick with 7500 mile changes as Subaru recommends, and probably not bother with full syn oil.

George
 

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Thanks !

By the way, is it very important to have oil filter with "anti drainback valve" ?
The Fram Toughguard that I got doesn't have one.
I understand that anti drainback valve is needed if the filter gets clogged up completely. If I will be changing oil every 3k miles I shoild be ok ?
They all have ant antidrainback valve as far as I know. Look in the small holed on the top and you will see rubber inside the holes.
 

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Discussion Starter #11
You have your valve names wrong. The anti drainback valve is a diaphragm that seals the inlets of the filter when the engine is off to keep the filter full of oil. The ensures that you get oil to all engine parts quickly.

The relief valve is the one that lets oil bypass the filter element when it gets totally clogged or may come into play if, on a really cold start, the filter element can't pass enough oil. As far as I know, every filter has a bypass valve, but the pressure settings where the valve releases may vary a bunch. Subaru OEM filters use a high psi setting and most aftermarket filters seem to be generic and have a lower psi setting.
My mistake:icon_biggrin: I meant the "Bypass Valve".
Some basic filters don't have it like the Fram ExtraGuard which I got. The more expensive Fram ToughGuard does have this valve.
 

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My mistake:icon_biggrin: I meant the "Bypass Valve".
Some basic filters don't have it like the Fram ExtraGuard which I got. The more expensive Fram ToughGuard does have this valve.
All can type auto oil filters have a bypass valve, period. There are different designs but they all have one. Try searching "Ed White oil filter" for his test and cutaways of a whole bunch of different brands of filters--you can see the different approaches used. He examines filters used by Ford V8's (including the one on my van) but other filter types are built the same. You can also see the cheap cardboard end caps used by Frams.

I believe all can type filters have the anti drainback valve as well, but the better filters have a silicone adb valve (more flexible in cold temps than the nitrile rubber adb valve used in lower priced oil filters).

Cars that use cartridge type filters (like my '91 BMW 318is) have only the paper element that is replaced, with the bypass function in the engine itself.

George
 

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My mistake:icon_biggrin: I meant the "Bypass Valve".
Some basic filters don't have it like the Fram ExtraGuard which I got. The more expensive Fram ToughGuard does have this valve.
Some models have visible bypass valves and others have a cheaper version that does not have the visible spring. If its a 7317 double guard. tough guard, or extra guard it will have the bypass.

Disclaimer:
This is information I believe to be true. The reason I am confident though is that any of these filters can be used in vehicles not having an internal bypass. Proceed at your own peril/risk.
 

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All can type auto oil filters have a bypass valve, period.
Actually there are some for GM vehicles (having built in bypass valves) ..that the filter will not have a bypass valve. GM 2.8, 3.1, 3.4 are examples.
 

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I've been using the Bosch from AutoZone for about $6.50 or $6.99.

I have an '04 non-turbo SOHC but look up an older Forester to get the bigger one instead of the newer, smaller, recommended one.

I think there is a recommendation somewhere for newer turbos to go with the newer, smaller one because the bypass valve operates at lower pressure, ensuring full oil supply under all conditions.
 
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