I recently noticed the radiator in the van leaked a little water. So a bit of barsleak used. The interesting thing is the water only seems to leak out the bottom somewhere when the radiator cap is undone. The tube from the plastic radiator bottle is clear and unobstructed. Today went for a drive of 130kms and when I stopped no water. An hour and a half later I undid the cap and water came out of the bottom somewhere. Then stopped. I doesn't gush out but it like a pressure valve letting go.

Which side does it come out on, drivers or passengers side???????????

Passenger side. Underneath.