Fan constantly on, Dell Inspiron 15R, Ubuntu 12.04

Problem

I installed Ubuntu 12.04 on a Dell Inspiron 15R. As soon as I boot, the fan starts at full speed and stays constantly on. I've seen similar posts, where installing fan control apps are recommended like

i8kmon  
jupiter
mesa-utils

but in general, these do not allow for automatic fan speed control and one has to manually set the fan speed, while keeping track of the processor's temperature. See: Similar post.

Technical specs

 - Processor: Intel® Core™ i5-3337U CPU @ 1.80GHz × 4
 - RAM: 6 GB
 - Disk: 500 GB
 - Graphics: Standard Intel drivers
 - OS type: Ubuntu 12.04 (64-bit)

lm-sensors

coretemp-isa-0000
Adapter: ISA adapter
Physical id 0:  +45.0°C  (high = +87.0°C, crit = +105.0°C)
Core 0:         +40.0°C  (high = +87.0°C, crit = +105.0°C)
Core 1:         +45.0°C  (high = +87.0°C, crit = +105.0°C)

Any hint on how to solve this ?

I have the same notebook as yours, and the solution for me was 'i8kutils'. In this package the script 'i8kmon' is for automatic control.

Some tips are:

• Put ENABLED=1 in /etc/default/i8kmon
• Put set config(auto) 1 in /etc/i8kmon.conf

I hope it helps.