leaking antifreeze on 1990 Buick LeSabre

I have a 90 buick lesabre. And it is continually leaking antifreeze, yet, I do not show a leak. Any suggestions?

Asked by for the 1990 Buick LeSabre
when the intake manifold got a crack in it, all antifreeze was leaking into intake insidei don't know for sure, but my 98 lesabre was losing antifreeze