Suggest you investigate rerouting/ supporting fill tube to remove any water traps, which can be a winter freeze risk and a mold risk issue. During maintenance on my 17yo at the time, found mold and rust residue and replaced mine. Suspect I may remove annually to sanitize, too, as solution does not sit in this tube. .
2000 Conquest LE 6266, Class-C on 99-E450SD, 6.8, 2v, V-10