[Eljaro]

Condensation would not produce the white slik you saw. So check for a leak.
Easiest thing to do: first take off your valve cover and look down the intake flanges. See if you spot water there. Especially the front, where the water passages are.It could be the intake gasket or a porous intake manifold (did happen to me).
If you see nothing, do like pirate says, put pressure in the cooling system.
I would connect a hose with compressed air where the temperature sender is on top of the intake behind the expansion tank(maybe some type of adapter needed). Take the spark plugs off and listen.You will find the water leak within seconds. If it is a head gasket failure you will hear it through the spak plug holes.If it is in the intake you will see it looking down the flanges.
Good luck.