Stranded- Need help with 97 Taruas-Head Gasket???

My girlfriend has a 97 Taruas that is experinecing some cooling problems. The coolant is bubbling out of the resvoir tank. We have already had the system pressure tested with out any results. We have replaced the thermostat and it is still bubbling over. The oil has no signs of water in the oil. However, I am starting to think it might be the head gasket. Does this problem sound like a head gasket or should we get the waterpump looked at first. How much $ would it cost to get the head gasket fixed? I am visiting from the Jeep forum but All responses are appreciated!

I used to have a 91 Taurus and I had that problem a couple of times. Twice, I replaced the radiator cap and it seemed to fix the problem. In the process of trying to figure it all out, I replaced the thermostat two different times. I replaced the gauge sending unit on the car twice also. Is the coolant level going down? Is there white-greyish exhaust or antifreeze coming out of the tail pipe? That would indicate a bad head gasket. The other thing you could do is touch the upper and lower radiator hoses. They should be about the same temp. as it is warming up. Careful not to get your fingers caught in anything. If they are not and one is quite a bit cooler than the other, there may be some type of blockage or air in the system. Take a look at the radiator cap though. When they don't seal right, they will boil like that.

The temp in my Taurus really climbed in the summer to where you would think it was getting too hot. The fan would finally kick on and it would go way down. Once though, it vapor locked when in the mountains when it got too hot.

my bet is from our experience with the 94 GL wagon with the 3.8.... sounds to me like the head gasket. Previous owner was blowing the top off the bottle as you describe. We had issues with them having the radiator fan going in the wrong direction. It started to overheat and they hard wired the radiator fan to a switch in the car - thinking that was the cure. Twice we turned the fan blowing towards the engine as it should always be - her ex kept turning the fan wrong. We pressure tested the cooling system and found a small leak. Car would not get heat and that is what made the call to tear it down to the head. Comphression tests are a bite on the back plugs by the firewall. For us we found only one side of the head blown, front side by radiator, but did both sides. If you are losing the heat in the car that should be a big sign you are looking at the head in our experience. We did not find any oil in the water or water in the oil neither. Dealer here in Colorado wanted 875 + parts for the head job alone. If you can do it yourself you save a ton. If you have someone else do it shop around.