They go from corpse they can smell, to corpse they can smell.
They'll eat until they can't smell any other corpses.

I don't know if zombies would ever feel the sensation of being full. They don't feel pain, feel very little of it, don't understand it, or don't care about it. That's nervous system related, as is the sensation of being full.

Fair enough, I guess it just feels a bit off that they get to chain corpses non stop. A physical limitation based on their bodies' capacity could also make more sense that a nervous system response

Well, this is where I like the game CDDA for it's zombie variety. Fat zombies are a thing, and depending on the tileset you use, crawlers are often portrayed as having half a body:

I imagine they'd eat till they burst, potentially ripping their body in two, becoming a legless crawler. The usual trope is they can't be stopped until their brains are destroyed, so, being ripped in half from overeating wouldn't even faze them. Catch here is, even after becoming a legless crawler, they'd continue eating, forever, with no repercussions, as it'd all just pass through them.

The real question here is are they even feeling hunger, or is it just pure aggression with no limiter, a desire to just kill, bite, rip and tear. Feral, in other words. If they do feel hunger, it'd stand to reason they could potentially feel full, but they'd also feel everything else. I'm open to debate on this.

That all said, zombies in the game have no truly unique IDs, so there is no way to track them indefinitely. Any hunger meter / cooldown would reset when they get loaded (leaving the area, and coming back, reloading the save, etc). Same if you were to track the number of corpses eaten, to turn them into fat zombies, before becoming crawlers: they'd reset to normal zombies when they are reloaded.

zombies that eat too many corpses should turn into l4d boomers :)