My new filter cutter arrived via UPS while I was cutting the lawn last night so I was able to cut the POS Fram filter apart without contaminating any evidence.

The basic problem was that the filter appears to have gotten plugged up! There is a really tiny filter element in that thing and I seem to be sheding old black deposits now that I have switched to Mobil 1. The oil was changed last in January and I have put only 3500 miles on it since the last change so the amount can't have been excessive.

Once the filter plugged, the relief valve appears to be stronger than the rest of the filter's construction. The actual filtering element is a center perferated metal tube with fiber end plates and the filter medium is folded and glued on the ends to the end plates. The sheet medium is closed at the joint by a folded/crimped metal piece. This element seemed to have been compressed end-wise enough to allow it to loosen in the housing. It is held in the housing by a metal stamping on the bottom that incorporates the bypass pressure relief valve. At the top there is a rubbery plastic part the serves both as a seal to the housing and as an anti-drainback valve. With the element compressed, the seal feature was no longer working so the oil was just going in the inlet and directly to the outlet! In addition to the compression of the element, at several places where the bottom of the folds were at the center tube perferations the medium had blown right through the hole. It looked like someone had used an awl to poke the holes.

I then used my new tool to open a couple of unused Fram filters I had for my Corvair and the wife's BMW. (Corvair uses the BMW filter with an adapter.) An old one, circa 1991, that had rusted a little was of a different design. It had metal supports on both ends and I would have felt comfortable using it except for the rust. The new one had the same cheap design as the failed Volvo filter. However, while it was twice as long the diameter and pleating of the medium seemed to be the same as in the Volvo application so its capacity was almost twice as great. The newer one had the upper end plate glued off center such that the seal seemed to be questionable! These 15 or so POS filters are going in the trash! It's worth the $100 or so it will take to replace them for my peace of mind.