I manage a website that has a separate client handle there DNS and email. This site has been unreachable for over 48 hours due to this external companies DNS issues.

Is it possible 48 hours of down time could hinder SEO results in any way?

depends upon site to site & crawling. 48 hours i think will not make difference i has same exp four 5 days nothing changed ..

Search engines do understand that things like this happen so if they visit once and see pages down it's probably not too big a deal. But if it lasts they could decide the site is down so I would try to get everything resolved as soon as possible.

I had an issue a couple of weeks ago where my server was down one weekend. Google came by and couldn't find some pages, which they reported to me through Webmaster Tools. The were reporting a couple of dozen pages not being found. I just checked and now I only see 2 pages not found.

It probably meant less traffic for me from Google the last couple of weeks, but everything should come back to normal.

I don't think there's an absolute number of hours where it will affect you, but the longer the site is down the worse the situation might be. Just try to get it resolved as soon as possible. Whatever you lose should come back once search engines see the pages are back.

No problem.sometimes it takes time.i had same kind of experience too.have patience.Surely it works

It will not.. In worst case it will effect temporary by dropping you a couple rankings...I had similar experience...The client's site went to #2 then came back to #1... (not on my server)

Thanks