One thing I have not seen mentioned (forgive me if I may have missed it) with lower intake gasket replacement is to make sure to do an engine flush and oil change after replacement because it's a good bet some Dexcool leaked into the engine. Another thing to do is stop using Dexcool and use the traditional green anti-freeze. If you want to stay with Dex I would recommend a cooling system purge (not just a flush) no longer than every 24 months or 24 thousand miles (whichever comes first). Best of luck to all of you experiencing this problem. I've been there.