I revived this thread because I thought I had discovered something new and exciting, when in fact it's already been discussed. Living in HI for the past 3 years I've been deprived of Autozone (where I used to buy Bosch filters), so I've been using the NAPA Gold (#1334). Last week I picked up a Bosch 3110 at Autozone here in CT. When I changed my oil and pulled off the NAPA 1334 I was surprised at the size difference. Looking a bit more closely, I noticed that the NAPA filter's end plate is slightly concave, so that the threads probably sit about 1/16"-1/8" or so below the filter O-ring. The Bosch 3110 (which is the same size/shape as OEM as far as I can see) has the threads nearly flush with the O-ring. I've been using the NAPA Gold filter for 3 years now, and although the threads aren't as high as the OEM filter, the thread engagement is more than sufficient.
I went back to Autozone and confirmed that the Mobil1 M304 has the threads even deeper - probably 1/4" or maybe even more - below the filter O-ring. I tried one of those out years ago (as I said 3 or 4 years ago in this thread!
) and only got 1 or 1-1/2 turns on the threads before the O-ring was against the engine block. Not good.
One additional bit of info. The same day I changed my oil I crawled under my Dad's '01 Outback wagon to find where it was leaking oil. His car has a filter on it that I've never seen before - longer and thinner than the little squatty ones I'm used to. It says "Fuji Heavy Industries" and "Genuine Part" on it (along with a bunch of Japanese writing) but I didn't see a Subaru emblem on it. It's possible that I just didn't wriggle around enough under there to find it the "Subaru" name on it. Or maybe it doesn't say Subaru on it. That made me wonder if it's some sort of generic FHI filter. I know Ford makes 2 different "grades" of parts - Motorcraft and FRPP (Ford Racing) - maybe Subaru and FHI do the same? Or maybe Subaru has shifted over to using filters made by its parent company rather than by Purolator? Does anybody know? Anyone have a newer Subie that can measure the OEM filter?
'97 Legacy 2.5GT sedan