I would say it does sound like the bowl drain valve. I had the same symptoms on mine, it was was worse when it was cold. I think after you get a little heat under the hood the o-rings expand and the leaks are fewer. Anyway, I replaced mine with the blue o-rings from guzzle. You can down load PDF instructions from his website. It was fairly easy to do, even for a mechanical dummy like me. Replacement O-rings for Ford Diesel Engines