Near the beginning of the game (Test Chamber 02 to be precise), right before you find the single-portal gun, you fall down a shaft and into some water. Wheatley asks
Can you see the portal gun?
He then continues:
Also, are you alive? That's important, should have asked that first.
I'm–do you know what I'm going to do? I'm going to work on the assumption that you're still alive and I'm just going to wait for you up ahead.
I'll wait–I'll wait one hour. Then I'll come back and, assuming I can locate your dead body, I'll bury you. Alright? Brilliant! Go team! See you in an hour! Hopefully! If you're not… dead.
– Portal Wiki
I didn't really have the time, but if you actually stand there for an hour, will he come? I realize this is pushing the bounds of game development, but it is Valve we're talking about here.
Best Answer
No, unfortunately, he never comes back to look for you (I tried waiting). It's not like there's anything down there that'd actually kill you within an hour anyway, and there doesn't appear to be anything in the script to the effect of him traveling back and calling for you, after that line. Still, rather unfortunate.