Subaru practices lean manufacturing, and as a result if they can eliminate part numbers to keep things simple they will greatly lower their costs, but there are some unintended consequences sometimes.

Nowhere is this more obvious than their oil filters and how they have changed, superseded and morphed through the last few years.

The O.E. oil filter you buy for your older model Subaru today looks nothing like the one it came with or was installed for years, but in Subaru’s quest to keep things simple they have decided to not make available the older oil filters, but instead have shrank the size of the filter and dropped the older part numbers from production and inventory.

Pictured below are the last 3 oil filters used by Subaru for the 4 cylinder model.  The black one in the middle was first used on the 2002 WRX turbo models, the reason for this is the Turbo models exhaust system runs very close to the oil filter and it was necessary to shrink the filter down to keep the oil filter from getting to hot and thus increasing the oil and engine temperature.   Here is where things have gone from there, we used to install the black filter on the turbo models, the white filter on everything else except for the H6 and the Loyale.   Then Subaru dropped the white filter from production, but wait a minute any one can see the white filter is bigger!   The oil filter now used by Subaru on all 4 cylinder models is the blue one, which is even a little smaller than the black one and yes still much smaller than the white one that was used on your non Turbo model Subaru for years. I also want to point out the location on the engine for the oil filter on the 4 cylinder Subaru models has not changed since the Legacy came out in 1989.

If you own a Turbo model Subaru and don’t change your oil and filter at least every 4,000 miles you will most likely buy a Turbo or worse an engine, this is the current theme in the 2005 and newer Legacy GT, Forester XT and Outback XT models.

Before there is any argument about synthetic oil and oil analysis, the oil filter used by Subaru is very small and will not last the 7,000 miles your synthetic  oil may last, oil analysis has no way of catching the slow clogging of the oil feed line to the turbo.  Damage from extending the oil changes can happen very gradually over time or can ruin your trip in mere seconds and be very costly.

If you change your oil twice a year versus 3 to 4 times a year you will save roughly $800.00 over a ten year period.  The bad news is you will most likely buy a Turbo and the Turbo will cost over $1200.00, just for the part!  Add to that labor, gaskets and the possibility of the Turbo damaging the Engine just for fun.

If you own a older model Subaru (pre 2005) and the dealer is now installing the blue filter you are now cutting the filtering capacity and oil capacity down from how it was originally designed, and if you exceed the ability of the filter to filter, it doesn’t filter and contaminants in the oil will circulate around in the oil rather than be caught in the filter, this is done as the filter becomes restricted by the bypass to protect the engine from ever being starved for engine oil.

Subaru changed the exhaust lay out of the header pipe in all of their four cylinder models to resemble the Turbo models and now all of the 4 cylinder models have the exhaust system running very close to the oil filter rather than on the turbo models.   So all current production models get the small oil filter as such there is no need for Subaru to keep making available the bigger oil filter even if it would be more beneficial to your 2004 Outback or your 1992 Legacy.

At our shop we use the Blue filters on cars still covered under A Subaru warranty to just keep things simple, and try to explain that the ramifications of going to long with the little blue filter won’t show up until the car is out of Warranty and its all your car.  We install a large oil filter on models that don’t have a turbo or newer exhaust system.  For turbo and 05 and later models we use a filter closer in design to the black filter as the Blue filter leaves a lot to be desired and anyone (minus the engineer who designed it) when holding the blue and black filters in their hands side by side will agree the quality of the filter is just not the same as it used to be.

The good news is Subaru did lower the price of the blue filter a little.

When I see things like this I will always try to find a solution to deliver more value than just going along with a corporations desire to cut costs.  While I will also never claim to be as clever as the engineers, I will also never lose the argument that reducing oil capacity and filtering capacity is a bad idea.  I kind of seriously doubt accounting ever consulted the engineers anyways.

Thanks for reading

Justin