When I turn off the car power steering fluid comes out of the reservoir under the cap, like there is alot of pressure pushing it out. Is this just a faulty cap? or is there some sort of pressure that is malfunctioning in some way? It does not leak when it is running only right after I turn it off. 95 Infinity J30

Optional Information:
1995 Infiniti j30

Already Tried:
tightening different clamps adding more power steering fluid.