I think Sivir
would be a viable support.Here's why,she has a spammable q once she gets a chalice 
or some mana item, her q is one of the most damaging spells in the game and her ult is really easy to use if a jungle comes or to disengage or engage from a teamfight, she also has pretty good aoe with q and w and she can save her carry pre 6 if your good enough to body block a spell with your shield.
XIII Vanitas4 votesSivir will never be a viable support. No cc, no utility except for her ult, no way to peel for an adc. Why do you want Sivir to play support, just for her ult? The active of Talisman of Ascension does the same thing and it's one of the three gp10 items for supports.
Stefanisbanda1 votesSona has no cc except for her ult either, and i want to play sivir support cause and she has great poke and dmg and utility with the ult, also if your good (mentioned this like 70 times) you can body block a spell for your carry with e, also im sick of the meta and wanted to see if something new would work, also a support wont have a talisman on lvl 6 when you can use it for a jungler to gank or to get away from a ganking jungler
JustMyBassCannon2 votesSona has no cc except for her ult either,
and i want to play sivir support cause and she has great poke and dmg and utility with the ult,
She has all the things that Karma has, except Karma doesn't need to be higher than level 3 to be good.
also if your good (mentioned this like 70 times) you can body block a spell for your carry with e,
If it's Morgana or Braum, sure. Most everyone else has AoEs and/or targeted CC instead.
also im sick of the meta and wanted to see if something new would work,
So don't run with a support bot lane, run with an assassin bot lane. Try Ashe/Talon.
also a support wont have a talisman on lvl 6 when you can use it for a jungler to gank or to get away from a ganking jungler
And Sivir won't have anything to prevent a gank before level 6. Even post-6, saying that her ultimate could avoid a gank is a stretch.
Stefanisbanda1 votesHow is it a strech? it leaves everyone around her sonic fast
JustMyBassCannon1 votesYeah, assuming absolutely no one uses any CC at all, you can run away with her ultimate. It's a mediocre means of escaping a gank.
Every single support and tank has stronger disengage than Sivir's ultimate.
Stefanisbanda1 votesSo soraka and zilean have stronger disengage? bit of a stretch there
Icestar11861 votesZilean has the stun if he hits two bombs, and Soraka has the silence/maybe root
Stefanisbanda1 votesBut how long does it take to charge up two bombs and how long does the root last that you can just walk out of it
Icestar11861 votesQ-E-Q=stun
If you place the root well, they can't follow you without getting caught in it, and it lasts 2 seconds, IIRC.
JustMyBassCannon2 votesBut how long does it take to charge up two bombs
Half a second, because his W refreshes his Q cooldown. Add a quarter-second for the travel time.
and how long does the root last that you can just walk out of it
If you're trying to snare with Soraka's E, instead of trying to deny movement, you're not doing it right. You either use it to keep them from using a gap closer/escape, or you use it where their dash/blink takes them to keep them from following up.
JustMyBassCannon1 votesZilean has stun threat with his double-Q as well as his E's massive slow/MS boost.
And yes, I would even say Soraka has stronger disengage. She can screw over engages with Equinox, and her low-cooldown heal can keep her ally alive through a lot.
XIII Vanitas2 votesIf you want to play Sivir support, do it, have fun. But don't ask if she's viable as a support, because she isn't and she'll never be.
Sukishoo3 votesSona has a Slow, speed boost, stun and shield/heal. Tons of utility Vs Sivir that has a speed boost.
Mew Goes AD2 votesYou also do no damage with no items and have no CC.
If you just want to spam harass, you might as well use Lulu or Sona.
Stefanisbanda1 votesThe cc part is true, but the base dmg on your q is one of the highest in the game and unlike lulu and sona you can stay from a save distance and spam it
aaronautumn1 votesi'd rather have support ashe or caitlyn. sivir has no utility and needs damage in order to be useful.
Stefanisbanda1 votesI think her ult is a bit of utility and caitlyn's stun is a bit hard to land, also sivirs q has insane base dmg
IcyPepper1 votesA good support needs some utility outside of their ult. Even Sona, who has no hard cc outside her ult, still has sustain/shields for her adc and a movement speed boost on top of her poke. Even poke supports need a little something on the side.
Caitlyn has her net and her traps which at least do something, and Ashe has vision, permaslow, and poke.
Stefanisbanda1 votesI guess if you argue really hard you could say that her e could be useful to the carry if you body block a spell with it
IcyPepper1 votesIf you were really good with Sivir and wanted to support with her, then I suppose you could.
Stefanisbanda1 votesYeah just sick of the meta and wanted to try new things XD
IcyPepper1 votesThe key to meta-breaking is understanding the meta, how it works, and how to work around it. Healthy meta-gaming is when there's multiple strategies present, and the meta of this game is stale because there tends to be one.
But that's not quite always the case.
If you want to do an off-meta support, think of what supports do and what your favorite champions can do to fulfill that. Some people can support with 
, some people cannot.
Sightless661 votesThe base damage on her Q won't stick up throughout the game, and her W will end up doing practically no damage. The spellshield only has self-protection, so it's also going to provide you with very little value as the game goes on. All you'll really be contributing is the ultimate, and you can itemize for that kind of speed boost on a support.
You could make it work, but only so far as you can technically force anything to work. She would always be worse than another option you could take. As far as I'm concerned, that means she wouldn't be viable. Do it if you think it will be fun, but don't expect good results.
Stefanisbanda1 votesI agree on the w part but the q is really good early game,and late game are supports really made to do dmg?? it still does decent dmg and pushes people back
Sightless661 votesThe Q is pretty good early game. For laning, it will still be heavily limited by the mana cost and the inability to throw though minions. Other supports have poke that is just as good, and they'll have better autoattack harass with standard autoattack ranges. Later game, it will do a bit of damage, but it will be the only thing she has that does damage while other supports have entire kits that might put out utility or damage.
and late game are supports really made to do dmg?
Depends on the support. Some supports will bring quite a bit of damage late game. Some will bring utility. Some bring a combination of both. Sivir will bring neither. If I really need a speed boost that bad, I'll take a Karma. Better laning phase, better utility at all stages of the game, and poke that is almost as good. Or, I'll take anyone else, and I'll buy a Talisman and/or Righteous Glory.
It's a bad pick man. If you think it will be fun, go for it, but it is always going to be inferior to other support options. If I can do it with Sivir, I can do it better with someone else.
BeatzBoyFTW1 votesSivir is so so so so useless when she has no CC compared to a Leona or Braum. Even more useless when she can't even do shit to save her ADC from a gank.
Stefanisbanda1 votesshe cant do that much pre 6 other than block a stun with her sheild but after six she has a great speed boost
BeatzBoyFTW1 votes
can already fill the spot. Sivir's ult is pretty much just wasting a slot for useful CC when those 2 items were commonly built & gets the job done.
DíckWallace1 votesAnyone can have a Sivir ult if they build Talisman of Ascension. There's nothing Sivir can bring to the table that a meta support can't do better. Her Q will be useless mid and late game without damage items. Mikael's Crucible is better than her E. Anything Sivir does can be accomplished just with items alone.
Erockandroll1 votesMost AD supports I have Seen, wined up being kill lanes. And these kill lanes are usually cheese that won't work on a higher Elo.
Part of the reason I say this is that you end up with a Double AD bot lane, which becomes easy to itemize against. Against said lane I can go with a Tank Support and stack Early Armor. Even with a poke support, I can take a Frozen heart instead of my core Mana Item and still do fair.