oil filters?

[matt167]

I service both my girlfriends 2004 wrx and her moms 2011 Legacy. I've always used the longer version of the filter on the 2011 Legacy but bought the listed filter in the Purolator on the wrx because I read it was designed and specd originally for the 2005 up wrx and then the books were adjusted to include 2002-2004... Is it safe to run the longer filter on the wrx so I buy 2 of the same? This is Pl14610 vs 612 iirc.. I've been reminded both cars are due.. They get 3k changes.

[Bushwick]

If you are changing at 3k mile intervals and preferably running synthetic, just run what it calls for. If the WRX has a turbo, some filters have an anti drainback valve at the back of the filter (pretty sure it's called an anti-drainback). If you use the wrong filter, it might be problematic in the long run.

 

 

I've switched to larger filters in other cars before (space permitting) and a couple times the short filter had the valve and others the larger filter did, so I did NOT swap. 

 

 

Get the filter it requires in one hand, then get your larger filter in the other. Look down through the center threaded hole, and look all way to the back. If you see a disc with a spring on one end, that's what I'm referring to. Whatever the filter the car is required to have, is what you observe. So if the factory style filter doesn't, then make sure the larger one doesn't have it and vice versa. I think the valve is typically on turbo'd cars (pretty sure my Saab has one) and NA engines lack it.

[keith3267]

Almost all aftermarket filters have anti-drainback valves in them now, some are better than others.  With or without the valve, larger oil filters take more time for the oil pressure to build up, maybe only a second or two, but its cumulative.

 

Modern engines are well sealed, the fuel is accurately metered so the only contamination comes from the oil itself as it gets old and breaks down.  Oil is getting much better now and lasts longer before it starts breaking down.  The bottom line is that the filter just doesn't have as much to do in modern cars, so smaller filters can be used.

 

Even the smaller filters are designed to last at least 7500 miles on modern engines.  I would recommend that you use the specified filter and not a larger one, especially since you are way overkilling the oil change schedule.

[Bushwick]

I would recommend that you use the specified filter and not a larger one, especially since you are way overkilling the oil change schedule.

 

That's not overkill, especially if they are running conventional. If you baby the car, it can go longer. If it's turbo'd, you should do it anyways as the turbo bearings are TINY and need constantly fresh oil or they can mar, plus the added heat from the exhaust housing is constantly heating the oil and the possibility of oil coking exists within, which is why so many run oil coolers. If the engine is driven hard, top shelf synthetic can darken by 3k miles.

 

When it comes to the engine, there's no such thing as too many oil changes

[mikaleda]

The bypass valves might have the wrong pressure limit as well on the larger filter and may put more stress on the oil pump when cold. I would say that you should run the specified filter for your car and just keep your oil changes on time no exceptions. Also get the filter at least one step up from the bottom of the line, I like wix personally

Edited September 28, 2015 by mikaleda

[matt167]

I normally use Napa gold wix premiums but read the pure ones for the wrx were designed for them.

[Fairtax4me]

Let's throw filter media area into the mix here along with the other sects of oil filter religion.

A larger filter is not always better. As a filter is used its filtering efficiency increases due to the capture of particles. A new filter is designed to collect particles down to X size (10 micron, for example), for Y amount of time before it reaches its optimal filtering capacity. As it collecs those particles that are 10 micron and larger, the open passages in the filter become smaller, thus allowing it to capture smaller particles. This is when a filter reaches its optimum filtering efficiency, capturing as many small particles as possible.

 

Using a larger filter increases the time it takes for a new filter to reach optimum filtering efficiency, thus allowing larger particles to continue circulating in the oil for a longer time period.

 

 

 

The simple truth is, changing the oil frequently, and using a quality filter will do more for engine longevity than using a larger filter. Use the filter that is specified, and you'll have no issues.