Not sure what has happened, whether it’s physically broken or something went wrong with the software. So the machine overheats fairly quickly now. This is running Debian 11 (bullseye) and /proc/acpi/ibm/fan says:
status: enabled
speed: 0
level: auto
so I don’t know if the heat is being recognized. The CPU does clock down as it gets hotter. I’m not getting any type of overtemperature alerts though, and I haven’t found any place in the acpi tree to read the temperature. That’s annoying since there must be some sensors in there.
It looks like there is a program called “thinkfan” in trixie so I might try to upgrade the machine tomorrow. I can only do so much at a time before the box gets too hot.
Any help? Thanks.

Just to be clear, I really meant to disassemble the fan until you hold in your hand the plastic thing that rotates (at which point you can really clean it, and take the opportunity to add a drop of lubricant on the axle).
Mental note: Send monnier my next smoker owned PC if I want it cleaned properly.