Pushing out water

[rdoc29]

I have 1990 Supra Turbo that is pushing water out the overflow tank. It is not over heating. It has a 13 pound pressure cap on the radiator. Forty thousand miles ago it had the head gasket replaced. Which did its job until now when the above started. I had it checked and the mechanic said it was the radiator cap which I had just replaced that and the radiator but he replaced the cap and charged me $125.00 for the cap and test and it still pushes water out. My question is should I try another radiator cap and should I put a higher pressure one on and if so how high of one should I go? If it is not over heating does that mean it is not a head gasket that is the problem? The reason I replaced the radiator was just to rule it out. I can definitely see the water coming out the hose of the overflow tank. I fill the radiator to the top and I fill the overflow tank to the maximum line and than I go for a ride and the over flow tank fills to the top and the water starts to come out its hose. The temperature gauge in the car stays between cold and hot if I had to guess I would say about 150 degree. What are your thoughts and suggestions? There is no water in the oil!