Bending the tube back was in the Ford Service Bulletins as a fix to coolant loss. I don't know how thoroughly they researched it.
The baffle does a pretty good job of stopping the coolant that's coming up the outlet hose, out of the engine, from hitting the underside of the cap. Ford's theory was that the coolant bounced off the radiator cap and went down the overflow pipe. My '29 radiator baffle is sloped like shown in the drawing.
I bent my vent tube to be vertical, not bent all the way back like they show. I know people who have put a roofing nail in that vent tube to stop coolant from splashing up and going out the overflow. I have also known others to extend the vent tube up, like Jack describes, with a piece of rubber tubing, like fuel hose or vacuum hose, to reduce the coolant loss.
I have seen several cars that had coolant loss like this, out the overflow, and not been able to stop it. The cars do not seem to be boiling over, it seems to be more tied to extended operation at higher RPM, like above 35 or 40 MPH. They could drive for weeks under 35 and not lose a drop, but run for an hour at 45 RPM and have a quart or two of coolant gone.
It is not possible to "see what's going on" in there while running down the road. I have my suspicions but no proof. It is odd how some engines do this and others do not.
