I have an Elan S3SE FHC. The cavities for the throughflow ventilation grilles in the roof pillars have a vertical lip at the lower outer edge which effectively forms a small bund in each in which water can collect. There is no drain hole in either cavity — in fact a drain hole would just empty into the car interior. Is the water just supposed to evaporate? Has anybody found drain holes in these cavities in their cars?
John Larkin
Mine has a depression at the base of the vent aperture to allow water to flow down the outside of the body. It’s a 1968 car so maybe the mould was changed to overcome the problem you face. Pic below, blown up from a full-car shot. I can’t take a better detail pic at the moment as the car is currently not here. (In fact it’s up at Lotus, having expired on the Lotus test track while being driven by a Lotus engineer for a magazine feature. It chose very carefully the moment when its gearbox decided that it should not relinquish second gear while third was being selected.)
John
John, I was intrigued by you question so I took of my vent (Sprint FHC) and put water on it, the water it does gather slightly but as the front of the vent slopes slightly forward and there is a piece cut out of the fiberglass at the front most runs out,
The vent also protrudes from the body so rain from the roof does not run in to it so I don’t think it will cause any problems.
John M. My Sprint does not have that depression at the bottom of the vent and it is a Oct 72 car…more strange things from Lotus 
Oh! I have just seen both of your cars that the vent is not protruding from the body…Lotus must have made the changes on later cars.
Thanks John, that makes sense. I’ll add that modification to my (long) do-list!
John Larkin.
Brian, I have just seen your reply. I found a photo of a Sprint I used to own and the roof vent has a raised lip on the front edge, and ramped lips on the tops and bottom edges. It seems that my S3 was sold before they discovered the problem that they solved by incorporating the drain as shown in John Simister’s photo.
John Larkin.
Curiosity got the better of me and poked and levered the tab/flange at the centre of the bottom lip — and it popped off, leaving a clearly visible cut out just as in John Simister’s photo! The left side drainage cut out was also filled in, but not to the same extent as the right side. I had the car painted yellow from its original blue in 1978, and it seems apparent that the guy who did it filled in the drainage cut outs. I never noticed till now…
John Larkin.