My 1997 Buick Century Needs a new head gasket? How much can I expect to pay?

This is been a terrible last few months. Both used vehicles are racking up the miles and they're starting to get worn out. My Buick got a bit overheated. The temp gauge red lined, and I immediatley pulled it over. I waited about 20 minutes and nursed it to my local garage. My mechanic has told me she was way low on coolant and he found no leaks from any location. Seems some antifreeze is possibly blowing out the tailpipe. So big money or what?|||Hard to say the heads should be removed perhaps they will have to be skimmed.


As the engine overheated liners could be damaged.