I have recently replaced the expansion tank on my 1989 1.9 diesel extra van. Since doing this I can't get the system to fill correctly. There is no water in the top radiator hose and despite bleeding it for (literally) hours I have had no success. I have replaced the thermostat assuming it was sticking but still I hvae a dry top hose. Strangely, the van is driving fine and not overheating but I suspect that I am not doing it any good by driving it like this. I have a 400 mile drive to undertake in a weeks time so really want this resolved before driving that distance. Any ideas?????