Damn thing is driving me nuts. Am I the only one whose suffered a leak at this thing? O ring looks bran new and I gave a shot sealing the thing with a little 1211. Today out I had oil once again all over the back of motor and it nearly convinced me I actually had a head gasket leak, was even on the top side of charger. Took it home...cleaned it up...quick 10 sec idle with mirror and flashlight and I saw the underside of sensor and 1211 was all blown right out..wtf...how much pressure behind this little o ring on the senor held in with one little bolt? I watched as oil trickled down from the base of sensor and ran right on top of base gasket. I'm going to go to hardware store tomorrow and see if I can find an o ring a tad thicker. The o ring doesn't even seen to show up in the microfiche I've looked at. How tight these things pop in? It does go in a bit loose and a faint pop and it seats but does wiggle about a bit making me think this might not be the right o ring.