My corrado was leaking from the cylinder head flange thing, i didn't figure it out until i popped the bonnet after a long drive and saw a tiny bit of steam.....
The flange itself should only cost about a tenner and is mega easy to change, i'd try that first and see if it cures the problem. Apparently they are prone to cracking (although mine was fine, it had been sealed with silicone instead of an o ring, which was the issue!!)