Water temp sensor value??

Does anybody know the resistance range for a B2200 water temp sensor? The ambient reading is 410 ohms, 500 installed in the block. I subed in a variable resisitor and have to crank it down to 30 ohms to get the guage to read in the normal range (half scale). The sensor is new and the guage cluster is a salvaged unit. The temp would read low or not at all with any combination of the old cluster/ salvaged one. A direct short to ground reads off scale high as it should. I also checked the voltage from the cluster 9.3v to ground without a load, it reads 2.3v at about half scale using the resistor. I am in the process of changing the radiator, it sprang a leak. Any ideas? If anyone has checked thier resistance/voltage at normal temp please let me know what the reading was. thanks.