filters with o rings vs flat gaskets

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Originally Posted By: edwardh1
do the 0 ring ones like denso ever fail? seems the flat gasket type like fram and purolater would give more sealing area?
I have used Toyota(Denso made) and Denso oil filters for a lot of years and have never had a problem with sealing. I like the Denso feature that precludes the filter being overtightened. You just tighten the filter until it stops and that is it. Actually, I think an o ring design will seal better than a flat gasket.
I've been using (on-n-off for Toys, pretty much regularly on my Hondas) with O-ring type (denso, toyo roki, etc.) oil filter seals for 20 yrs now, no failure so far.

Counterpoint: if Toyo Roki, Denso, etc (denso uses a semi-round o-ring type oil filter seal) been manufacturing and using them on pretty much all their assembly line and dealership servicing engines and oil change jobs w/o any failures, one cannot see why this does not work (or would fail).

Afterall: NA being litigious society, you bet this problem would be blown out of proportion (on mass media, bashing, etc.) if it's such a bad idea.

Good day.

I've worked at a Toyota/Lexus dealer for about 19 years & never saw 1 OEM O-ring type filter leak. I've seen hundreds of the flat type gaskets leak
No difference at all. Neither type will ever leak unless there's an installer error (old gasket left stuck to filter boss, for example.)
It's just two different ways to achieve the same thing. O-ring gaskets are thinner but put more pressure on what's touching the block, preventing leaks. Flat gaskets have a wider sealing area which prevents leaks. Both work.
O rings are designed with calculated deformation. That is how they seal. I recall that our EHC units at our power generation facility used four bolt Parker flanges which used o rings. You installed a new o ring, torque the bolts down to Parker specs and they never leaked at 3000 psig. Almost foolproof but some nose picker could find a way to fubar the most cogently written maintenance instructions.
Only thing I don't like about O-ring or P-ring gaskets on an oil filter is they allow the metal base of the filter to make contact with the mounting face, and it can cause some chew marks in the metal. When I used Denso Toyota filters, I would ensure the metal lip where the filter makes contact with the mount was nice and smooth so the metal-on-metal did minimum damage. Of course the damage is outside the seal, but still I don't like chewed up stuff.

Also, with the O-ring design, you have to ensure you stop turning the filter just when the metal-to-metal contact occurs. Cranking on it much beyond that increases the metal chewing, and could potentially really lock the filter onto the mount when trying to remove it later.
I've used the STP S2808 which uses an O ring style sealing gasket with no issues. It seemed odd to see that style though.

Once had a P-type gasket drip/leak on a dealer installed Toyota Denso oem filter. Took it back and dealer replaced filter, said there was a recall. But who knows if that was true or just blowing smoke for an improper installation. But I did try to tighten the filter prior to returning to the dealer and it made no difference.

Flat gaskets have worked fine, always making sure to apply a thin layer of oil prior to installation.
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