Bmw

I have a bmw 325i 2006 . recently i had oil flow into
my coolant reservoir. We changed the oil filter
housing gasket because it was cracked and broken
we also changed the electric water pump and
sevral coolant hoses , the car runs fine and doesnt
overheat it just keeps gushing the water back after
a while i can run the car for about 5 minutes with a
full water tank before i need to get off and put
more please help guys btw there is no more oil in
my water reservoir . thank you guys.