First of all was the coolant filled using the proper procedure ? If not there could be an air pocket.

Second a Tstat cannot be designed to failsafe open, and EVERY time that engine overheats the stat could go bad. Luckily they are cheap.

Third the radiator could be clogged at the bottom.

To check it out, first of all run it with the radiator cap off, I DO NOT mean the reservoir, I mean the radiator itself. Some actully do not have one but that vehicle should. Fill the water and rev the gas using the throttle. If the water comes up you need a head gasket at least. If the water does nothing try a water pump, I have actually seen them with broken impellors internally.

If the water does suck down, regardless of if the Tstat is open or not, suspect the radiator itself. It could be half clogged. You have no way of knowing except maybe to run the vehicle until it gets really hot and compare the temperature of the top and bottom of the radiator. The top will always be hotter but, then you have to guage how much. Let's put it this way, if it is about to boil over and you can put your hand on the bottom of it, it's clogged. However on that vehicle I dount you can do that.

Got one of those heat detecting gun jobbies ?

Anyway, unless you have an EXTREMELY wierd engine management problem or a head or head gasket leakage, I have the solution. I have done it a few times because you don't **** around with two things - cooling and oil.

If I verified that there was no head/gasket problems I would get a recored radiator, a new water pump, thermostat as well as hoses. And a belt for the hell of it. Put it all in at once and then follow the proper filling procedure.

First of all in my cars, even though it is not recommended, fukum - pure antifreeze. You put it in and then start it. You run it as it sucks it down. THIS TAKES TIME. you keep on filling it and filling it until it starts coming out, BUT before you call it full you MUST see the coolant circulationg. You will see it spurting out the tubes inside the radiator.

However if it doesn't have an actual radiator cap, which is not that unusual anymore, there will be an air bleed, most likely at the top of the Tstat housing, but not always. A 1997 vehicle should be as I described, and a Ford will be using a conventional cooling system, not a polypropylene or oil based system so what I said should apply.

Before investing all that money though, run a compression check just to make DAMN SURE you don't have a headgasket problem. They are more common than people think. If you DO need headgaskets, get Felpro Printoseals, the metal kind.

It will run better than ever, and I am not kidding. The metal gasket is usually thinner which will raise the theoretical compression ratio. If it's a V6 (likely) with hydraulic lifters there will be zero compression once you install them. Pull the ECM fuse to turn off the injectors and let it crank under that no load condition until it starts sounding like a car engine rather than an electric motor. Throw the fuse back in and start it but DO NOT touch the accelerator. Let it idle however rough, even if it stumbles and stalls, DO NOT rev the engine up.

After that you wil not only have a nice cool running engine, but more horsepower than you were used to. Believe me I have done it. Of course you only gain that if the new gaskets are thinner than the originals. The Printoseals usually are, they are the equivalent of shaving the heads.

J