I remember there being two sizes of a paper filter, one long, and one short. The short one wanted the spring. I seem to recall Wix 33044.
I also remember that they both chugged up in no time and were a pain to swap as the aluminum casing they live in would strip its threads if you looked at it funny, and I could never remember which way the filter goes -- they're directional and almost, but don't quite, flow properly when backwards.
I removed them and went with a much larger external inline filter, e.g. Wix 33033.
-- A