Make sure the fan is operating first. This era of Ford used a single module that controls fuel pump operation, A/C operation, and cooling fan operation. There were normally referred to as ICRM or CCRM modules (Integrated Controller Relay Module or Constant Control Relay Modules) but had a name change depending upon the year. Basically it was a low tech “box o’relays…”.
The above items consume a lot of electrical current and at times a poor connection would develop at the ICRM/CCRM connector because of this. The usual suspect was erratic or no cooling fan operation. Sometimes it was curable by loosening the bolt that holds the connector on, unplugging it, and then plugging it back in.
I’m not saying that the ICRM/CCRM or connector is the cause of a problem; only that it’ a possibility IF the cooling fan is inoperative.
The 3.0 is a very good engine and not prone to head gasket problems and personally, I always like to think a problem is comparatively minor instead of suspecting the worst.
Some evening after the engine has cooled you might loosen the radiator cap to relieve any pressure that exists. Retighten the cap and go to bed.
The next morning raise the hood, start the engine, allow it to run for 20ish or so seconds and then hurriedly loosen the radiator cap. If you hear a noticeable hiss there may be a head gasket fault. If you hear nothing or very little then odds are the head gaskets are fine.
That’s backyard testing at its finest…