Disconnected the passenger side hose off the thermostat and had an o-ring and a plastic ferule tumble out. Neither of these came with the new thermostat, are in good repair, so I'll reuse them. I'm having trouble refitting the hose on to the new thermostat. I put the ferule on first (tapered side facing away from the thermostat), o-ring next, line up the grooves, and...nadda. Any suggestions?