One of the common problems with the Jaguar XJ40 is that water leaks past the bottom of the windshield into the heater fan and onto the feet of the driver. The Jaguar Forums offered several suggestions and talked about a “duck bill” that is part of the problem. My first attempt to address the problem didn’t fix it. I sealed up what looked like the bottom half of a duck bill below the finisher/cowl under the windshield but still water got into the passenger compartment.
Finally, someone answered my questions and pointed out that the “duck bill” was a rubber cover for the drain below the windshield wiper motor in the engine compartment. It took a while for me to see it as it looks like several other hoses near the firewall. But I finally felt around and realized what it was. After removing the “duck bill” I was able to clear the clogged drain of dirt. Now I can run water on the windshield from a garden hose and the water just pours out between the firewall and engine. Hurrah!