Ok folks this si strange.

Changed oil and filter yesterday @ 10K miles.

Inside the oil pump housing at the bottom of where the oil filter sits was a small soft rubber o-ring that had been broken. It is about 1/2 inch in diameter. I could find nothing that had a small O-ring missing. There is what appears to be a relief or bypass valve, but it did not appear to have any missing O-rings.

Anybody got an idea whre it might belong???

 

Maybe on the filter itself? Did the new filter have a similar gasket on it?

 

Another alternative, look at the filter housing. Look inside, I remember a gasket about that size inside.

 

I've looked at everything in the housing and in the metal part that the housing screws onto. The olny place that there is even a round indention that size is around what appears to be a pressure relief/bypass calve on the bottom of the housing receiver. But it pushes down, not up and an O-ring in that location would simply never contact anything. Athe orifice at the bottom if the relief valve hole is much too small for this o-ring to have passed through.

Here's a picture of the ring beside a dime for comparison

 

Found the same o'ring in the same place in the daughter's car at its first oil change @1,000 miles. There's no mention of a similar o'ring in or near the oil filter housing in the parts book (I checked with the dealer parts guys and looked at their computer drawings). The only thing I can think of is an o'ring from above the filter housing (oil pressure switch?) that gets bungled during assembly and left for dead in the filter housing by the engine assemblers.

 

Well.... I've gone almost 400 miles since I found it. Thre's stil oil in the motor, and nothing seems to be leaking. Sacred myself half to death because the little warning triangle came on beside the odometer, but then when my bllod pressure went back to normal I remembered that I had also moved the tires front to back and had forgotten to reset the TPM. Great relief when it went away.

I can only conclude that whatever the little o-ring was for, it was either unnecessary, or was a spare part that was somehow left inside the motor as you suggest.

I just hope that at 50001 miles the engine doesn't suddenly blow up for lack of an o-ring.

Something to just forget -- I hope.

 

Add me to the list...same O ring, split at the same place...looking at the realoem part blow up picture...it's not part of the filter assembly...looks like the best guess would be from the timing chain guide retainer bolts

 

36000 miles since I found mine. Still no issues. Still a strange thing to find inside the motor.