picked up some oil change supplies today. i asked for the usual fl-2051 filter. when i got home i saw it was a fl-2051s. anyone use this? its got some type of silicon anti-drain back valve inside. suppose to help with cold starts. just curious if anyone notices a difference during cold starts as i have never seen a 2051s before.

 

With the filter mounted vertically, you are not going to get any drain back as you would on an engine with the filter mounted on the side of the block where it is in a more horizontal position.

My guess and humble opinion is the FL-2051 was sold at the dealer and has a Ford part number on it also and the FL-2051S is the commercial version sold at part stores and Wal Mart or similar box stores. I doubt there is any difference to be of concern.

 

ThE last filter that I bought at the dealer was an FL 2051S.

 

S stands for "silicone gasket", ostensibly an improved version. The last 6 or so filters I installed were all S versions and no problems whatsoever.

 

For my F-150, the "S" in FL-820s stood for the silicone anti-drainback valve. Apparently there were some aftermarket filters made that had a regular butyl rubber anti-drainback valve that would deteriorate over time on the 5.4 Tritons. Possibly the "S" is an improvement for your oil filter? The valve helps keep your oil passages primed, so there's very little waiting on getting oil pressure up into the heads and valve train.