adjusted the valve so it was not open as much. if i remember right it is a brass coil spring that expands and contracts with the temp of the coolant. as the crap builds up on the valve i work the spring more. the spring needs to be "reset". that is done by over tightening the spring. over tighten it a little at a time. I also have 10k in it since i cleaned mine and it has not gummed up or had any problems.