Once lm-sensors is installed you need to reach for your terminal:
type
sudo sensors-detect
just press ENTER for everything it suggests (shown in Uppercase)
At the end it will ask you whether to add what it finds to /etc/modules. If you are happy with the findings type "yes".
More information about lm-sensors and how to tailor it for your system can be found on the lm-sensors installation wiki page
Typing
sensors
will display the values for the sensors detected previously.
e.g.
acpitz-virtual-0
Adapter: Virtual device
temp1: +55.0°C (crit = +90.0°C)