Are you talking about the plastic valve you see at the far end of the
filter can when you look into it? That's not an anti-drain back valve,
that's a filter media bypass valve. It's supposed to open and let the
oil circulate around the media, instead of going through it, when either
the oil is too thick to flow through, or the filter media is too
obstructed.
The anti-drain valve is the metal ring or coil spring you see around
the base of the threads.
If you or anyone else wishes to learn all sorts of stuff about oil
filters, go to a parts store and request to see the AC/Delco filter
book. This book contains all sorts of information about the various
valves in filters, the media, construction specifications and such.
It's #1 for figuring out which various alternative filters will fit your
particular vehicle.
>>> "Steve R." <triumphtr6@cox.net> 01/15/03 01:57AM >>>
My 2 cents on the article
I have seen this article years ago and since then I always check to
see
the rubber valve on the filter. I don't remember if it stated it, but
for an example: Look at a Fram filter and the Fram Tough Guard filter.
The Tough Guard has a 'anti drain back valve", so when you shut the
car
back off, the oil that might be in the process of being clean does not
drain back into the pan.....well that's what I like to think..but it
allows the filter to retain oil when your vehicle is turned off so
your
engine benefits from a filter full of oil at startup.
I buy a couple of brands and that is what I look in a filter, because
it
does make sense. Ya you can talk about a filter being cheap etc., but
you should consider this in the construction of the filter. I do buy
Purolator filters because of the gasket and I think Allied Corporation
as the store brand soda at the local supermarket. :)
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