What is this vent.........

[Funkpirate]

and what is it for? There is one in front of the front roof exit,and one at the very rear of the roof. What is it venting,and what kind of problems will it cause when I patch and waterproof it? The roof leaks,and this is an apparent gaping hole.

Any ideas?

[Elliot Naess]

Without seeing more of your bus, I expect it is simply fresh air for the interior of the bus. I had a small one on Millicent, and I sealed it up.

Front engine buses can have problems with engine fumes getting inside. I solved this by cutting a big hole in the front, where the intake to the heater is. At speed, air blasts in thru the heater system much more effectively than before -- problem solved.

[Funkpirate]

O.K.,they're good as gone.............

[elkoskoolie]

My vent cover was a bit more domed and only open to the rear; I took the non-functional fan out, made a template and plumbed my black tank vent into it. Used black corrugated tubing for a washing macine drain, or was it sump pump drain tubing... Anyway, that's a good use since it is an existing hole in the roof.

[wmah]

it seems to be only on school buses. If you look at transit buses such as a bluebird transhuttle there is not one there at all. So it can be patched up with no worries. I left mine open as it didn't leak and I figure it gave a spot for the hot air to rise out of.

[GoneCamping]

There is a hollow channel about 2" wide that runs the length of the bus in center of the roof where there is no insulation. This channel and those vents allow the heat to escape out.

Mine had a tendancy to leak when it rained, but since I didn't alter the roof I figured they were important in some way, so I left them. But to control the leakage, I bought some home type vent covers at Lowes and put them over those vents...