Could be.
I remember an old Dell that after it got some years on it just started to heat like no other.
To the point where it would stutter and lock.
Now I cant remember if it was anything particular like the nvidia card .. that machine had met its end of life.
In your case, I do suggest a clean up like @Fabby mentioned above. Especially if its old and never had that kind of treatment, you might be surprised to find anything from a ton of dog hair to an ant colony in there 
But of course there are more software avenues too, like TLP, thermald, and/or some of these power savings help with heat too: