If you’ve been doing a good job of keeping the cat hair and crud out of the heat sink then the only things that can cause it to heat up that much are a failed fan or a glitch in the fan’s controller. I know that my T135 had a firmware update for that one.
Now, I am going to ask a dumb counter-question; the fan is still spinning, right? If not then there’s your problem. Even if it is, sometimes they drag, causing them to spin slower and thus move less air.
One other final thought that is highly unlikely but I feel I must mention simply because I’ve been there, done that, and got the crappy T-shirt is that the heatsink got knocked loose and thus an really do it job as well. Given how tightly things are packed and how solidly they are mounted (usually) I honestly doubt that that’s it, but it is a possibility. I don’t suppose it’s had any rough knocks, lately, has it?
@lillycoyote Personally, I have never used one of those. Maybe part of it is that I tend to get laptops that are designed for longer battery life and that reduced power draw naturally leads to less heat and thus easier cooling. At the CFM ratings of the average laptop fan, the added space underneath won’t matter, and if you need more fan than the laptop came with then I can’t help but wnder what other design flaws the laptop has.