Engine is overheating?

Im not sure but its leaking on the passenger side if that helps a bit. The engines gauge is showing the engine is not hot though but after driving a few minutes it heats up and starts leaking antifreeze

The guy is telling me because the car been sitting that there is air and he needs to let it bleed but I dont know what he means

Engine Cooling problem
2000 Ford Taurus 6 cyl Front Wheel Drive Automatic

originally I did not have any heat, we thought the heater core was bad because one hose was hot and one hose was not. That did not help so wwe then found the water fins were gone, replaced water pump. The car still overheated, we then replaced thermostat, still overheated, we then removed thermostat, still overheated. Replaced the radiator and all hoses, still overheated, purchased a kit that tests for exhaust in cooling system and passed. Replaced expansion tank and cap also, and both coolant temp sensors. The car will overheat sitting in garage after about 20 minutes. Any help would greatly be appreciated.

Yes both the fan sensor and the gauge sensor have been replaced, and both fans do work properly, I can turn on the heater and the fans kick on and still overheats

My car keeps building pressure and throws coolant out my fluid box. I've change the water pump because it went out. But tha didn't fix the prob. Help and it not the thermosta

Pressure test the system to see if there are leaks, pay close attention to the bottom side of your coolant resovoir, they are very common to crack on the bottom and leak out when car is warm, if no leaks and jug is not cracked, but car is overheating boiling out overflow, check cooling system for combustion gases in coolant with a chemical test diagnose head/head gasket issue.

Hey Doc, was still typing must be when you posted.

10-4, lol

First overheating was in Aug. 2011. Cracked one of the heads(other one was okay). I had the entire cooling system rebuilt: new radiator, hoses, water pump, etc. It ran good for a few months. Then in Dec. It started leaking coolant. The heads seem to be okay but one head gasket was blown indicating overheating again.
Before this happened in august I had taken road trips(from Dallas to Iowa and Colorado), and even around town, with no problems. Just wondering what may have caused it to overheat again.

Thank You for consideration. -Jeremiah

I suspect there is an engine coolant leak considering that I have bought two bottles of it. It just recently started over heating. I've had the vehicle for a little over a year and a half now. The problem just started about two weeks ago myb less. I've never let it get to the high temp. I usually turn the heater on full blast to cool it down until I get home. But I've seen leaks toward the front end of my car. How much would this cost to fix? Could I fix it myself? Any suggestions would be greatly appreciated. I'm very poor. So I'm worried. Thanks.