4x4van wrote:
The white connection is a different color than the spin-welded flange, and has ridges on it, suggesting that it is screwed into the tank flange. Have you tried backing it out using a large pipe wrench?
I kind of wondered that myself, but enlarging the OPs photo it looks like the threaded portion is slightly embedded into the different color of the plastic and there is no "nubs" on the light portion on the tank..
Click For Full-Size Image.
Compare to a spin on flange..
Click For Full-Size Image.
Makes me wonder if the plastic that when heated changed color some when it was spun..