While you're at it, check how much RAM it has. Some older, but not too much older, machines end up RAM constrained and can perform significantly better if RAM

While you're at it, check how much RAM it has. Some older, but not too much older, machines end up RAM constrained and can perform significantly better if RAM is maxed out (if prices for the older RAM have not become excessive). If you're opening the machine anyway to swap the fan, might be a good opportunity to upgrade RAM. Beware of spending more on the machine than is worthwhile, though.