Hi Graham,
Welcome to the site !!!
I just disconnected my fuel heater when it went out, left it in the bowl with no ill effects thus far. As far as your drain valve not working, I would order the drain valve repair kit and go for a o-ring replacement as listed here in the stick thread...
http://www.thedieselstop.com/forums/...-valve-130024/
Sounds like you have one SWEET Truck there with only 78k miles. Do yourself a favor and get rid of that K&N as soon as ya can man !!! Those things let all sort of stuff get through...
Removed K&N to find......
Again welcome to the site and I'm sure you will get a lot of replies here from the experts... it has been truly a AWESOME place to learn for me.
