Cleaning water jackets 225

Rad temps and such seem pretty normal and reasonable. My '62 Dart B body will read about 200 F at the t'stat housing after several minutes on the interstate at 65-70 mph with a recent rebuild and ambient in the 80F+/- range .

Did you put in the TS6178 sensor? If so, and the fuel gauge is accurate, then very likely it the the temp gauge in the dash.

Figure out how to read resistance with your meter, and then check the sensor resistance when heated; remove the sensor lead before testing, and check resistance between the terminal and the sensor metal body. If it in the 20-25 ohm range, then the gauge is about 99% likely to be the problem.

Again, this all assumes that the fuel gauge is reasonably accurate; the fuel gauge being accurate says the the voltage limiter is very likely working OK; that feeds limited voltage to both the fuel and temp gauge systems, so if either gauge reads right, then the limiter is presumed to be good.