I am having problems with overheating on my T420 laptop. I think this is related to my fan speed no longer adjusting. Here is the output of sensors without load:
acpitz-virtual-0
Adapter: Virtual device
temp1: +58.0°C (crit = +98.0°C)
thinkpad-isa-0000
Adapter: ISA adapter
fan1: 3575 RPM
coretemp-isa-0000
Adapter: ISA adapter
Physical id 0: +58.0°C (high = +86.0°C, crit = +100.0°C)
Core 0: +59.0°C (high = +86.0°C, crit = +100.0°C)
Core 1: +54.0°C (high = +86.0°C, crit = +100.0°C)
cat /proc/acpi/ibm/fan
status: enabled
speed: 3591
level: auto
When the laptop reaches high to critical temperatures under load, the fan speed does not increase to an audible level. It increases maybe 20% over the normal level. I have verified that the fan is spinning by checking the airflow. How can I troubleshoot this? I remember the previously that the fan would kick up to higher speeds with increasing heat, but this does not appear to be happening anymore.