RE: Do taylor made windows leak? Mainship 390 2004
More likely the install is the problem , tho low cost windows are just that.
Many are very simple to re bed , unscrew , scrape the sealant off and use a new roll of sealant , from the RV dealer.
It is quick and clean and does not cause the problems 5200 or 4200 cause on the next replacement.
All sealant has a limited service life , the RV tape is great on newer fittings built for it.
Dolphinite is my favorite for older more common marine parts.