Dan-e-boy,

It should not do what you are describing. Mine has never done that and it is quite old and used (...as evidenced by the scratches and crud) <img src="/images/graemlins/grin.gif" alt="" />

Try adjusting the valve on the bottom (toward the "minus")



I've never had a problem with over-filling it. I use a quality fluid and cram as much in there as I can. <img src="/images/graemlins/confused.gif" alt="" />

Hope that helps. If not, it may be damaged or defective, like groo said.