Duck and Cover

Is it possible to Sell the location of Vault 13 to President Tandi for some cash? Hell, with the sentient Death claws wiped out by Horrigan (or by you, you cold blooded bastard).

Hell, NCR consolidated Vault 15, the taking of Vault 13 would be icing on the cake.

No, I really doubt that such a thing is possible. I've never heard anything about that, so don't get your hopes up Rama.

Darn it... But really, it could be something to sell Vault 13 to NCR for loads of Cash.

Tandi mentions something about V13 being more useful to them than V15. I've been meaning to check this out m'self, but have forgotten about it every time I get that far into the game.

My hunch is that you have to let the DC die or wipe them out yourself before going back to talk to Tandi, but not have picked up the reward for V15 yet. I remember talking to her once w/the DCs still alive and she said that it didn't do them much good if there were DCs there.

Maybe one of the FO2 modders can lend some insight into this one?

Edit: But before anyone get their hopes up, I have to point out that V15 seems to be the crux of the NCR endings. Here's the only two NCR endings that are included in the game:

FO2 Devs wrote:1:Your help with Vault 15 launched the New California Republic's push to civilize its neighbors.
2:Though there were many more obstacles to overcome, the NCR now had a foothold into the northern wastes.

FO2 Devs wrote:1:The failure of diplomacy at Vault 15 slows the New California Republic's growth into the north.
2:Embarrassed by the failure, President Tandi is replaced by Roger Westin.
3:When the new government finally returns to Vault 15, they find nothing but a ghost town.

OTB

The Nearly Ultimate Fallout 2 Guide by Per Jorner seems to cover this pretty well. Search for "If you discovered Vault 13" for information about giving location of V13 to Tandi and "NCR established" for all the NCR endings. I can't vouch for it's accuracy though so far it hasn't let me down.