Today, I was hopefully successful in unblocking the water drains in my car.
As I mentioned yesterday, there are a couple of pipes that run down the interior of the car, which drain water that collects in the seam of the convertible roof. The excellent miata.net forums provided the solution, which was an inexpensive trombone cleaning snake. Essentially, a long, semi-rigid wire with nylon brushes at the end. Once you figure out how to get the snake into the drains (it takes a bit of visualization), you push through until it comes out the bottom of the car, and then repeat the process a few times.
I first tried it yesterday afternoon, but couldn’t figure out if I was missing the drain openings (which you can’t entirely see) or if they were completely blocked up. I went at it again today during a brief, rain-free period, and now I’ve got the hang of it. The passenger-side drain seemed to be reasonably blockage-free; however, there was a bunch of debris jammed in the driver’s side, and I had to wrap the snake around a coathanger in order to give it a bit more force. After that, the snake went through without issue, although I was expecting a bit more dirt to come out the bottom. Hmm.
I need to eventually run some hot water through to flush out the drains, but it was cold and started to rain again. Thus, I declared a tentative victory and went back inside to warm up.