What's that thing inside the oil filter?

QA Guy · 07-12-2003, 07:09 PM

For some reason, I was looking at and inside some of the Purolator oil filters that people here have mentioned as being compatible with the 2002 WRX and I noticed a difference.

The x14460 (which I have been using) and x14459 have something attached to the inside top of them with a U bracket.

. __
_| |_ <- looks like this (ignore the dot)

Others, like the x24458 and x24457, which look compatible, only taller, do not have this thing.

So... what is it?

Thanks!

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CharT · 07-12-2003, 08:40 PM

Are you talking about the orange rubber flap that's blocking the holes? If so, then that's the anti-drain back valve. It's for engines that have the oil filter mounted sideways. This prevents all the oil from draining to the bottom of the engine. It's supposed to keep some oil in the oil passages so you get oil pressure quicker when you start the engine.

QA Guy · 07-12-2003, 08:45 PM

No, I don't believe so.

This thing is held on by a metal bracket and is present on filters, like the L14460, that don't have an anti-drainback valve.

CharT · 07-12-2003, 10:04 PM

Then that's probably the bypass valve. It looks like a spring-loaded metal flap, right? Filters are supposed to have a bypass valve so if the filter is too dirty and clogged, oil can bypass the filter media and flow to the engine. Dirty oil still lubricates better than no oil at all.

QA Guy · 07-12-2003, 11:43 PM

Yes, upon further inspection, it appears to be spring-loaded. I think that you're right.

Thanks!

07-12-2003, 07:09 PM	#1
QA Guy Scooby Specialist Member#: 6739 Join Date: May 2001 Location: Houston, TX Vehicle: 2002 WRX Silver	What's that thing inside the oil filter? For some reason, I was looking at and inside some of the Purolator oil filters that people here have mentioned as being compatible with the 2002 WRX and I noticed a difference. The x14460 (which I have been using) and x14459 have something attached to the inside top of them with a U bracket. . __ _\| \|_ <- looks like this (ignore the dot) Others, like the x24458 and x24457, which look compatible, only taller, do not have this thing. So... what is it? Thanks! * Registered users of the site do not see these ads.

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07-12-2003, 08:40 PM	#2
CharT Scooby Newbie Member#: 36117 Join Date: Apr 2003 Location: Bay Area, CA Vehicle: 2003 WRX Wagon WRB	Are you talking about the orange rubber flap that's blocking the holes? If so, then that's the anti-drain back valve. It's for engines that have the oil filter mounted sideways. This prevents all the oil from draining to the bottom of the engine. It's supposed to keep some oil in the oil passages so you get oil pressure quicker when you start the engine.

07-12-2003, 08:45 PM	#3
QA Guy Scooby Specialist Member#: 6739 Join Date: May 2001 Location: Houston, TX Vehicle: 2002 WRX Silver	No, I don't believe so. This thing is held on by a metal bracket and is present on filters, like the L14460, that don't have an anti-drainback valve.

07-12-2003, 10:04 PM	#4
CharT Scooby Newbie Member#: 36117 Join Date: Apr 2003 Location: Bay Area, CA Vehicle: 2003 WRX Wagon WRB	Then that's probably the bypass valve. It looks like a spring-loaded metal flap, right? Filters are supposed to have a bypass valve so if the filter is too dirty and clogged, oil can bypass the filter media and flow to the engine. Dirty oil still lubricates better than no oil at all.

07-12-2003, 11:43 PM	#5
QA Guy Scooby Specialist Member#: 6739 Join Date: May 2001 Location: Houston, TX Vehicle: 2002 WRX Silver	Yes, upon further inspection, it appears to be spring-loaded. I think that you're right. Thanks!