93 ford taurus wagon. heat problems

my 93 taurus wagon 3.0 v6, acts like it over heat. We changed the thermostat it wasnt that. The fan is working, so its not that, what else can it be?

Possible head gasket leak into cooling system will allow super heated gases to drive up the coolant temp. Are you losing coolant? If so, get a pressure check done on the system. Another possibility is the waterpump is shot and not circulating. I had one go on me when the shaft broke and it wasn't circulating the coolant and there was no coolant loss. Good luck.

What do you mean by it acts like it is overheating? Are you just judging by the guage, or is it running sluggish, etc.?

-Rod