[~The Jester~]

If it's a head gasket it depends where it's blown. If it blew between combustion and coolant, then you get the white smoke out the exhaust for sure, possibly white creamy oil, and possibly oil in the radiator. If it blew between oil and coolant, you get white creamy oil.

Sounds to me like a head gasket. Especially since you have "brown stuff" (oil) in the radiator. Usually an intake gasket won't do that. Since the cooling system is pressurized, it's tough for an intake gasket to put oil in there since there's no pressure on the intake side. A blown head gasket will use cylinder pressure to force oil into the cooling system. 180+psi cylinder pressure vs. 16 psi cooling system.

Good luck, let us know!