Recently, my 02 Sebring Convertible 2.7L started overheating. When I looked under the hood, I found that the seal on the Water Outlet Housing came loose. One repair shop at first told me that "well, that's a common thing, we have BOXES of those parts here, it's not a big deal to fix." but when I called the next day, another mechanic st the same shop told me that the repair would cost almost $400 because they would have to take the intake manifold off to replace it. My question is this, can I just seal it back down with some sort of sealer? Will that work? The mechanic told me that I couldn't, but the 1st mechanic said that I might be able to. I'm taking it on a trip this Thursday and I don't want to break down. Also, could this also cause A/C problems? My A/C seems to leak all freon out within a couple of days and now I can only get it to work while on 4??

Any help will be greatly appreciated.