I purchased Pro-Tec oil filters after reading on this website that some folks were satisfied with them. I purchased three models for 3 cars (of course): Pro-Tec 163 Pro-Tec 167 Pro-Tec 130 The 163 and the 167 have a strange quality. I can't blow air or suck air through the mounting hole. I can suck air through on the 130, but not blow air through. I suppose it makes some sense that anti-siphon valves might prevent blowing into the filters, but it seems like I should be able to draw air through the mounting hole since that's the way the oil travels. I checked all 3 filters against counterparts I had in my garage (that I know work): Parts Plus PH2840 v Pro-Tec 163 goes on a Toyota I4 Pronto PO4006 v Pro-Tec 167 goes on a Chevy V8 Pronto PO241 v Pro-Tec 130 goes on a Toyota I6 On the PH2840 (163) I was able to suck air through but not blow air through (I could actually blow just a little air through). So they are different. On the PO4006 (167) I was able to both suck and blow air through. So they are different. On the PO241 (130) I could suck air through though not as easily as I could on the 130. I could not blow air through. So those two were consistent. Now I'm concerned about putting them on the engines and â€¦ well, you know. I'd appreciate any knowledge out there that would help me resolve my dilemma. Thanks much.