This was discusssed on another thread which I couldn't find. Anyway, the question deals with the Purolator Oil Filter for the Focus. The filter in question is a L25230 Premium Plus. The outlet has a spring loaded disc. The disc is push down into the filter on a seat. (The outlet is closedwith no pressure) When there is pressure the disc will come off of its seat and flow will come out the outlet. Now if there is too much pressure the disc will block the outlet-but not completely. There are 3 cut-outs on the disc that do not allow the disc to fully seal. The disc's other purpose with no flow is to act as a secondary antidrain valve and in the high flow condition it will limit flow.
Why would it limit flow you may ask- Well the pupose it to limit huge amount of unfiltered flow when the conventional bypass (at the bottom of the filter) opens. Also by limiting flow there will be a greater pressure on the outlet side of the filter. This will help reseat the bypass valve.
So in case you thought this was a top bypass valve which would limit dirty oil from the inlet of the filter from washing dirt into the outlet-bzzzt-wrong. However it would limit this because as I indicated it will reduce flow and thus limit this effect. In effect it's a poor man's regulating valve.
The equivalant K&N filter HP-2009 has no such device-in case you are interested.
Couple of other things: The filter has metal caps (it is about 1 year old). It has 67 media folds and media length is 3.5 inches long. Filter media area is 205 sq. in. There was a string around the media. The folds were uneven. Probably by design to avoid plugging with compressed folds. Cannister thickness was .009 at the outlet end and .009 in. at the bottom of the filter. I use this filter as a replacement for the smaller PL 10241 in my 2.4 L (22R-E) Toyota Truck. I'll take the K&N-thanik you.
That's it folks.
Why would it limit flow you may ask- Well the pupose it to limit huge amount of unfiltered flow when the conventional bypass (at the bottom of the filter) opens. Also by limiting flow there will be a greater pressure on the outlet side of the filter. This will help reseat the bypass valve.
So in case you thought this was a top bypass valve which would limit dirty oil from the inlet of the filter from washing dirt into the outlet-bzzzt-wrong. However it would limit this because as I indicated it will reduce flow and thus limit this effect. In effect it's a poor man's regulating valve.
The equivalant K&N filter HP-2009 has no such device-in case you are interested.
Couple of other things: The filter has metal caps (it is about 1 year old). It has 67 media folds and media length is 3.5 inches long. Filter media area is 205 sq. in. There was a string around the media. The folds were uneven. Probably by design to avoid plugging with compressed folds. Cannister thickness was .009 at the outlet end and .009 in. at the bottom of the filter. I use this filter as a replacement for the smaller PL 10241 in my 2.4 L (22R-E) Toyota Truck. I'll take the K&N-thanik you.
