I ordered a new thermostat for 180 degrees and a molded rubber upper hose to replace the corrugated one I have that may be reducing flow. The lower temp thermostat is to get it to start cooling sooner and slow down the cascade of events. I sent RA an email to ask them to make sure that pressure tester they sell will fit the neck of my radiator. 1.75" inner dia of the filler neck and 2.25 is the outer lip that catches the cap. I am using a Stant pressure relief cap with the lever in the middle 13psi. The picture they show does not show the inside of the cap on that tool so I can't tell if it is threaded which would not work or if it has the two lips to grab the lips at the top of the neck.