I had always thought the drain back valve was the rubber ring that you could
see through the holes surrounding the large threaded center hole. The NAPA
1515 had a diagram of the wonderful features, and showed the ring. I have
been reading bout the various filters used by folks on the net. Inspired by
the number of possibilities, and a sale at the local Track Auto I went to
buy some filters. Didn't see any ring on the Puralator, Delco, or Fram. The
only one that had the ring was the Ford. All were physically the same except
for the rubber ring that I had always thought was the anti drain back valve.
Here is my question. If some of the folks have been happily using Fram and
Purolator where are the anti drain back valves on those filters?
Jack
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