The absolute best remedy is to remove the whole mess, heater and all, and replace it with a standard IN-and-OUT filter-head that takes a better performing three-dollar filter.
I doubt that wimpy little heater with it's puny little wires adds over two degrees to the fuel temperature anyway.
Just about any company that builds filters also sells generic standard-thread filter-heads, to which a whole host of filters are available for whatever filtering need one has.
You can get single-filter units, or doubles, and even triples.
Most big trucks use a double for the fuel, with a water-separating coarser PRIMARY and a much finer SECONDARY.
These are pretty much standard, thus not so expensive.
The best water-separating filters have a solid bottom with integral, made on the filter, drain-*****; none of that two-piece open-bottom leaking crap.
