It may not be the headgasket Steve. More likely it is the rocker cover gasket. Clean the area up and check it closely. Pretty easy job in a van.

As for your friend. I wouldn't call him an idiot like ^ but no chemical additive will out perform new seal or gasket.

I'd save Bar's leak for I'm stuck in the desert with x amount of water and I have a radiator leak and don't want to die out here.