Ok, so the vent tube is fine. I originally purchased the correct seal - according to the rivergate instructions - from NAPA. That leaves that I installed the seal improperly. I can live with that. When I installed it, I used a wood dowel the same diameter as the seal and tapped it into place. I'm sure I checked the fit to make sure it was seated without distortion. I will pickup a new seal from the Nissan dealer. Is there a better, or more correct way to install the new seal? Thanks for all the input.