Take your spare tire out. This will aid in cooling till you figure out what
is the problem.Turning on your heater will also act like a radiater.With no
thermistat installed,I have to go w/bad radiater.When my water pump went
bad, water came out the pump berring profusley.I had to fill up with
roadside swamp water (atleast it was distilled,never mind the leaves).Dont
know how to check for a bad pump otherwise, except to remove a hose and see
if water pumps out fast.W/no thermistat, you can do this.Did the problem
occur suddenly or gradually and when the outside temp went up this spring?
If you have a/c,you can turn on the radiater fan by turning on the a/c.If
your going more than 30mph you dont need a fan anyway.Could be a temp
switch that screws into the radiater front if your fan does not turn on,or
a fuse.The fan itself is almost bullit proof.If your timing is way off,
your van may over heat in the city.