Anti Drain-Back Valve for Oil filter

[RoughDiamond]

Noticed this while changing my oil and filter, but the filter I normally use (Purolator PureONE) does not have an anti drain-back valve in the filter. Neither does the Fram, Classic, M1 or K&N. The only one that does is the MANN Filter. Haven't been to the dealer to see what the OE filter has.

Only reason I ask is that if the car sits overnight (or longer), it gets real chatty on start0up for approx 10 secs then quiets down. Doesn't do this when warm.

I only ask as I think this could help prevent a dry start as the filter fills back up. Thoughts?

[RoughDiamond]

Doing some reading, this might be of interest.

Subaru Oil Filters Explained

AWD Auto (Justin, at least) is convinced that we don't need or should use an ADB valve. The EG/EZ motors DO, but primarily due to the fact the newer EZ (3.0/3.6) have horizontal filter adapters.

Regardless, I'll be looking for the 15208AA031 or equivalent filters now.

[Legacy777]

The filter sits vertically such that the filter stays full of oil on the EJ series engines, so I agree they do not need an anti-drain back valve.

[RoughDiamond]

Small update on the filter stuff. Picked up a few 15208AA031 and turns out they won't work as the threat offset is too deep to make a positive attachment. The filter I've been questing after is the black Toyko Roki, 15208AA100. Yes, long discontinued and well coveted by enthusiasts.

However, I discovered the NPN brand filters are made EXACTLY like the AA100 filters, have the same specs and are even stamped with Subaru part numbers (albeit for a Justy). Available for ~$4 each.

But I am going to exchange my AA031 filters at my Subaru/Mazda dealer for some Mazda N3R1 14 302 filters. Made by Tokyo Roki, same diameter as the AA100, same bypass settings, media and construction, but slightly taller (for more media). I can't think of a negative against it.

I've got the NPN filter on order and will do a side-by-side to see once I have both on hand.

[mike-tracy]

At one point I ran a k&n filter designed for a porsche 944. Twice as long, but same diameter. Better flow and/or filtration? I don't know, but it was a special order at the usual parts stores so I stopped using it out of convenience.