i guess i should restate my comment im not very knowledgeable with arduino but i do understand how the code works. this is the code I'm referencing and it does update on its own. its basically identical to what i have aside from mine has the excess stuff from the speedo.
void loop(void)
{tft.fillScreen(0xFFFF);
tft.setTextColor(0x0000);
tft.setTextSize(5);
tft.setRotation(1);
tft.setCursor(0,0);
sensors.requestTemperatures();
Celcius=sensors.getTempCByIndex(0);
Fahrenheit=sensors.toFahrenheit(Celcius);
tft.print(" F ");
tft.println(Fahrenheit);